overstretched and now swelling / light pain

Hi all, feeling a bit foolish. Saturday at just over 4 weeks post surgery (lateral mammoplasty) I overstretched my left arm / chest - I felt a pull in my chest at the time but there is nothing visible. However, since then I have significantly regressed in how that area feels - back to tightness into upper chest / shoulder / uper arm and pins and needles / numbness in arm etc. I am upping my exercises gently as am guessing I have pulled the tissue / internal stitches and triggered some edema again... Anyone else ever had this or have any advice? Thanks.