What Causes Persistent Pain In Breast Radiating To The Collarbone?

I have been plagued the last 5 days with reoccurring pain up into my right collarbone. It kind of starts just above my breast and goes on up into the collarbone. It is worse at times than others. Sometimes just sitting and reading or watching TV it is painful so that I move and try to get more comfortable, but to no avail. The pain intensifies when I try to take a deep breath or yawn. Sometimes I can't do either of them because of pain. Ibuprofen does seem to help, but it always returns when it wears off. It does not affect my arm at all. I do not smoke and never have. I am 5'2" and weigh 120 lbs. I am fairly active and run several times a week (more of a jog).