So you enjoy being active and working out? Excellent.
Assuming some degree of body weight (pushups) and weights are being utilized, shoulder pain is a pretty common complaint.
Often mentioned as soreness or even sharp pain in the front, side and/or back of the shoulder; the causes for these symptoms can seem complex but often just need some simple yet focused attention.
In discussions about shoulder pain (and barring any sort of complex injury) the common diagnoses provided by MDs include all or at least one of the following:
Rotator Cuff Tendonitis/Tendinosis/Tendinopathy.
Let's define these terms to make them less scary to begin with. Any time you see the suffix 'itis' it simply means inflammation. So 'tendonitis' literally means the tendon is inflamed. 'Tendinosis' still applies to inflammation but indicates the inflammation has become more chronic (~10d - 3mon). Tendinopathy still applies to inflammation as well but indicates even longer chronic symptoms (beyond 3mon). These subtle nuances of 'aging' the inflammation are important because it helps me to understand how easily it will be to overload the irritated tissue.
As you progress/regress along the tendonitis --> tendinosis --> tendinopathy continuum the loading capacity of the involved tissue decreases.
Impingement is essentially a fancy way of saying tissues are getting pinched/compressed more than they're designed to tolerate.
Fairly simple, right?
In wrapping your head around where to begin with your shoulder pain you have to ask yourself if it feels more stiff and junky OR does it feel weak in certain positions or after a bit of extended work. It can be both for sure, if you feel like both categories apply to you then give a little bit of each group of movements/exercises a try.
Rounded shoulders and a stiff mid back can interfere with your ability to get your hands all the way over your head. Mid back stiffness prevents your ability to fully express your shoulders' capabilities.
If you're nodding/identifying with or even fixing your rounded shoulders upon reading that, try these:
Shoulder (specifically the rotator cuff) weakness or poor endurance can also be to blame for some of the inflammation. As the tissues are overused and cannot manage load appropriately, they respond by becoming inflamed. Continued overuse and poor load management strategies exacerbate symptoms resulting in you getting stuck on this inflammation & symptoms rollercoaster.
If you feel like your shoulder strength/stability could use some work the following are some light, introductory methods of strengthening the rotator cuff and scapular stabilizers.
As you begin to develop better strength and endurance on the back side of the shoulder, you can progress to more challenging positions/movements.
Fight the urge to jump right to the more advanced movements. You'll probably be able to accomplish them but wear out the weaker muscles faster and end up performing compensated reps. The introductory movements, performed perfectly and slowly, can be quite challenging on the correct tissues for a long, long time.