Hey Azmark,
The shoulder is a complicated joint and from your description it sounds as if you may be dancing with a rotator cuff impingement. Since it sounds as if you're not near an RKC, you're either working through this on your own or you need other professional help in figuring out what the pain generator is and what the faulty movement is. So, brief anatomy lesson...

The rotator cuff is comprised of 4 tendons that insert on your arm bone (humerus) whose function is to pull the humerus down and back into the joint as the arm raises above 90 degrees. They are aided in that endeavor by the stabilizers of your shoulder blade, mid/lower traps, etc. To cut to the chase, most modern humans experience problems here due to habitual postures that pitch the body forward, reducing exension in the thoracic spine and reducing the ability of the scapular stabilizers to hold the joint in place so that you can lever off of it. To build sustainable shoulder motion, work on extension flexibility in the thoracic spine and control with the scapular stabilizers. Rowing exercises will help, exernal rotation exercises with Theraband or sidelying with lightweight KB will also help.

McGill speaks of "bending the bar" with your lats when performing overhead presses of any kind. This helps to plug your shoulders into your core so that you're grounded. Try doing that with C&P and snatches and see if that helps.

Back to anatomy...the cuff tendons occupy a narrow space (subacromial space=SAS) between the humerus and a bone above called the acromion. When you raise your arm above 90 deg, that space is narrowed further. The postures above further narrow the space, meaning that if you have crappy posture AND raise you arm above 90 deg, then you increase risk of impingement. To test this for yourself, poke your head forward, rotate your arms inwardly and raise them. Feel how it's difficult to raise very high? Now rotate the arms outwardly, sit up straight and repeat. Easier, huh and you can go further. This little demo shows a free way to increase the SAS and lessen chance of impingement. Work on the external rotators of the arm and the scapular stabilizers and you're on your way. Another effective way to increase SAS is with acromioplasty surgery and you'll find any number of local orthopods quite willing to help you with that. Most folks prefer to sit up straight and do a little appropriate exercise first though ;-)

If you have injured the cuff tendons, then they swell, narrowing the SAS further. If that is the case, that needs to heal and the swelling resolve before you keep performing overhead lifts. Then you need to correct the form error that brought this on. Consider a good local PT or DC to work you up and get you back to training ASAP.

Hope this wasn't too much or too confusing. Cheers.

Dr. Phillip Snell
www.FixYourOwnBack.com/blog