19, inactive, tend to strain muscles often but last physical normal, no period in the last month but NOT pregnant , definitely. Yesterday, I was having a strange pain down my arm, and around the region above my right breast and below my collar bone (and in my back behind that area). Out of paranoia, I keep investigating my chest just in case. Lately I have been pulling muscles A LOT and sometimes have taken days to recover, so I was wonder if maybe since my arm was related with this, maybe my pectoral muscle was strained. I also get tense feelings in my other breast, but not as profound, so I thought another possibility would be the beginning of my period which I missed. I am receiving a physical from an internal medicine doctor on Friday, but do doctors also check for breast problems as well? How can I approach my doctor about this? I ve also had slight problems breathing when this all started in that same area, so I thought my muscle might be swollen.