What Causes Swelling In The Left Arm?

hi.. m archana. age 27 height 5 feet one inch weight 64 kgs...i have a sewlling in my left arm from a few months but thr is no pain n numbness...also smtimes thr is pain on the left side... i had a TMT done last yr in september n it was normal...but ther is still pain smtymes on the left side and thr is swelling in my left arm...plzz help