Sharp pain in posterior deltoid

About 2 months I was doing military press and got a sharp pain in my posterior deltoid-trap area. At the time it wasnt too bad, but the following day it wsa very sore. I couldnt even push ups without it hurting too much.
At the moment the exercises and motions that cause pain are lateral raises, any kind of benching or pressing move and push ups. Its definitely gotten better over the last 2 months, but it still hurts quite alot on the above mentioned exercises, and its always localised to my posterior deltoid area.
Has anyone experienced this before, or have some idea of what it is or what I could do to help it recover a bit faster. Im laying off weights of course, but the boredom and frustration of having my routine wrecked and knowing im losing the gains Ive worked to get by being out of the gym is really getting to me now.
 
Any input is appreciated. Thanks