I Have Been Experiencing Pain Under My Left Arm For

I have been experiencing pain under my left arm for most of the day - I believe it may be trapped gas - I have taken 2 zantax [sp?] and the pain has moved to a new location - I did take two blood thinners earlier in the day also and am wondering if this could be the issue - please advise... - I took one more blood thiner by accident - could this be the issue???