Pain in right shoulder blade.

I have had pretty bad pain in my right shoulder blade for about 6 months now. It is not constant and it appears when i sit down on my sofa or computer chair for more than 20 minutes. The pain is so bad that i have to keep my arm still and pray it goes away quickly. It usually lasts for 2-20 minutes and I just don't know what it could be! I have not done any rigorous exercise in a while and I have not lifted any heavy weights so i don't think ive strained it or pulled a muscle there. Please tell me what it could be and how to get rid of it thanks.

[squirtatious]

I too have had ongoing pain in my left shoulder blade region that extends up into my neck on the left side and into my left shoulder. Mines my trapizious muscle and foreward head syndrome that causes my pain.