Suggest Treatment For Pain In Chest And Back

I am 25 1/2 years old, 5 6", 56kg. Last week my G.P told me I had gastritis, went back today because the pain had worsened in my chest and back, especially when cycling to work yesterday, and then continued throughout the day at work. I felt like I needed to take my bra off at work to release the pain. This of course made no difference. I am feeling less emotional about it as I have been given a diagnoses today, but I was just wondering the cause really, I can only imagine it was after I had an abortion back in october,and was excessively vomiting and feeling sick while pregnant. Do you think this maybe the cause for both these diagnoses? I have previously been fit and healthy. My sister has 'sore rib syndrome' could this also be a connection?