The deltoid is a round muscle that goes around the top of your upper arm and shoulder. The main function of the deltoid is to help you lift and rotate your arm. There are three parts of the deltoid muscle that connect your collarbone, shoulder, and shoulder blade to your upper arm. The three parts are referred to as the anterior, middle, and back.

Read on to learn more about what to expect from deltoid pain and how it’s treated.

You’ll usually feel deltoid pain or soreness in your shoulder. Symptoms vary depending on the severity of the strain. Deltoid strains are classified in three grades.

Grade one

If you have a grade one strain, you can use your arm normally, but will have some tightness or soreness in your shoulder. Your shoulder may be slightly swollen.

Grade two

Grade two strains are partial deltoid muscle tears. With a grade two strain, you will have trouble using or lifting your arm normally. You may have sudden pain while trying to use your arm, and your shoulder will be moderately swollen.

Grade three

Grade three strains are more severe or complete deltoid muscle tears. Muscle tears can lead to severe pain and an inability to move your arm normally, or at all. Your shoulder will be very swollen.

Deltoid pain is usually caused by overusing your deltoid muscle without rest or proper warm-up. This increases your risk for a muscle strain or tear. A strained muscle may also be called a “pulled muscle.”

Deltoid pain is more common in people who do a lot of strenuous exercise involving the shoulder, such as:

  • weight lifting
  • swimming
  • skiing
  • playing baseball

You can also strain your deltoid muscle while doing repetitive activity that puts pressure on the shoulder, including typing with a keyboard that’s too high.

The first steps after you injure your deltoid are rest, ice, and heat.

Icing the muscle right after the injury will help reduce inflammation and pain. If you have a minor injury, 15 minutes on and 15 minutes off a few times throughout the day for 1 to 2 days should be enough. If you have a more serious injury, or if you still have swelling, you can ice for a few more days.

After pain and swelling are reduced, you can start to apply heat, usually one to five days after the injury. Throughout this time, resting your shoulder will help give it time to heal. You can also take over-the-counter pain relievers to help reduce pain.

Gentle stretching can also help reduce pain caused by a deltoid strain. Try holding your arm across your chest or raising your clasped hands above your head. These stretches will help increase your range of motion and flexibility. This can help reduce pain by allowing your shoulder to move more freely.

If you have a minor strain, recovery may take one to two weeks. An injury with partial tearing may take four to six weeks. A serious tear can take up to four months to heal. Rest, ice, and heat are your best first steps for recovery. You should continue to rest your arm until your pain starts to subside.

If you have a minor deltoid injury, you can ease back into exercising after a few days. You should not have to completely stop working out unless it becomes too painful. If you have a more serious deltoid injury, you should stop exercising your arm for at least one to two weeks to give it time to rest. Once your pain has decreased, you can start to perform strengthening and stretching exercises to help restore function.

If you start these exercises and find that you still have a lot of pain, stop and take more time to rest. Preventing reinjury is one of the most important parts of recovery. Focusing on restoring range of motion first will help you ease back into exercise without hurting yourself. Warming up before stretching or exercising will also help you prevent further injury to your deltoid.

Some stretches and exercises that can help you recover include:

  • Pull and hold your arm across your chest for 10 to 30 seconds.
  • Clasp your hands behind your back and stretch out your arms behind you. Hold for 10 to 30 seconds
  • Try isometric resistance exercises, such as pressing your hands into a wall.
  • Add dynamic resistance exercises once you can move your shoulder comfortably, such as bent-over and upright rowing, and overhead presses with light weights.

You should see a doctor if you have trouble moving or using your arm properly, especially if you also have shoulder swelling or sudden pain when using your arm. These are all signs of a more serious deltoid injury. If you can’t lift your arm at all, see a doctor as soon as possible. This is a sign of a severe muscle tear.

Your doctor should be able to diagnose your deltoid pain and its cause based on a physical examination and a medical history. Be sure to tell your doctor about any recent activities that could have caused the pain, such as weightlifting, swimming, or other activities that require strenuous use of your arm and shoulder.

You can reduce your risk of straining a deltoid by making sure the muscle is ready to handle strenuous activity, and by using the muscle properly. Use these injury-prevention tips:

  • Warm up before exercising.
  • Stretch daily to improve your range of motion and flexibility.
  • Rest after exercising. Take days off or work different muscle groups on different days.
  • Strengthen your deltoid muscles so they can handle more strenuous exercise. You should also strengthen your core so that it can help support your shoulders while you exercise.
  • If you work at a computer, make sure your keyboard is positioned so that your shoulders don’t strain up or down when typing.
  • Practice good posture.

Deltoid pain may slow you down for a few weeks, but you should recover with proper treatment. To reduce and prevent deltoid pain, you should:

  • stretch often
  • always warm up before exercising
  • take steps to reduce muscle strain

Minor deltoid injuries don’t usually require treatment from a doctor, but if you have trouble moving your arm or your symptoms last for more than a couple of weeks, physical therapy or orthopedic care can help.