Do your shoulders hurt when typing or driving?

The Deltoids

shoulders hurt when typing
The deltoid muscles make up the very superficial (closest to the skin) muscles of the shoulder. They help to hold your arm up when driving, typing or holding a tool. If your shoulders hurt when typing, you likely have trigger points in the deltoid.
There are 3 parts of the deltoids: anterior (front), middle and posterior (back). It is rare that trigger points (knots) are found in the deltoid alone. There are usually other muscles with problems too. The other muscles that can be problems are the pec major and minor, biceps, coracobrachialis, trapezius, supraspinatus, rhomboid, triceps latissimus dorsi, and teres major and minor. Don’t you worry! I’ll be covering all of these in the coming weeks!
The middle deltoid and the supraspinatus bring the arm out to the side. If you have trigger points in the deltoid, it will be difficult to get your arm to 90 degrees or you will have less strength than normal. People develop trigger points in the middle deltoid by repetitive, vigorous movements that bring the arm into abduction (away from the body).
The anterior deltoid brings the arm to the front of the body, to the face or across the body. Trauma is the most common reason trigger points are developed in the anterior deltoid. The biggest trauma is shooting a gun. The recoil hits directly on the deltoid. Grabbing a banister to catch a fall can also cause trigger points here.
The posterior deltoid extends the arm behind the body towards the glutes. Its other job is the help hold the humerus into the shoulder joint. Overexercise like skiing causes trigger points in the posterior deltoid.
Deltoid trigger points are commonly misdiagnosed as rotator cuff tears, bicipital tendinitis, subdeltoid bursitis, glenohumeral joint arthritis, impingement syndrome or c5 radiculopathy.

How to fix it

To help your pain, you will need to learn to lift heavy objects with the arm rotated so that the thumb is turned in the direction that takes the stress off the affected deltoid. You should take precautions on the stairs so you don’t need to grab the handrail quickly. If you like to shoot guns, place a pad between your shoulder and the gun. When typing you want to make sure that the chair is neither too high nor too low. You want the arms to be at 90 degrees. As always, you will want to stretch and get massages as often as possible!
Stretching the Deltoid heads & associated muscles by Kyron
Stretching the Deltoid heads & associated muscles by Kyron
*info taken from Volume 2 of Myofascial Pain and Dysfunction, The Trigger Point Manual by Travell and Simons.