<s>[INST] hello,my name is christina i feal roller skating about 4 months ago.i have been doing p90x.i have a knot in my arm that will not go away.i have been to the doctor 2 times.i have been taking inflamation meds.dose not seen to help.still hurts.what do u think [/INST] Hello! Thank you for the query. The knot can be caused by hematoma or ganglion cyst. Both can appear due to injury. Hematoma is caused by small veins rupture. Due to blood presence in the soft tissues, some kind of fluid collection appears. If its large enough, won't disappear by its own. Moreover, can get infected and turn into an abscess. Ganglion cyst is less probable, as it usually appears on the wrist. Ganglion cyst is more like a rounded and soft lump caused by tendon injury. I suggest you to have soft tissues' ultrasound of the lump area at first. This allows to determine the nature of such lump. If its hematoma should be Chat Doctor. Hope this will help. Regards. </s>