Suggest Treatment For Pain In Shoulder Or Collar Bone

a month ago, I woke up (in the AM) with a sharp pain in my shoulder/collarbone. It may be that while walking my dog, he jerked my arm around by his leash, but I can t really remember as I did have a couple of beers that night. The pain comes & goes (it s bad especially when I m sitting in a chair in my office) but today is really painful! If I press on the area, there is a big knot & helps when I rub it. I have a crappy health plan & will have to put out money if I see a Doctor. What can I do to help w/ pain? Do you think it s something serious? Beverly