Shoulder pain - help!?

I have had shoulder pain on and off for the last year now. Began under my shoulder blade. Went to 8 physio sessions, were they said did alot of movement tests, but i was able to do them all without pain! I seem to get a sharp pain when i move my arm certain ways, but i cant pinpoint a particular movement that is causing it. The last few days, the pain has increased, and i now feel it down my arm, and around my armpit area, and into my hand. Any ideas? The physio discharged me, as he couldnt find anything acutally wrong, and any treatment was having little effect. The pain is slowly becoming unbearable...and inconvenient when i have my 1year old to look after!