lump in armpit and under breast at bra line

it all started when i got a very cold in march that lasted 5 weeks. a lump formed in my armpit, also banged my elbow and fluid formed on my elbow and was told that can cause swollen lymph node in armpit. i also currently have sinus infection with fluid in ears. went to my doctor and she felt the lump in my armpit and says it is hard and really moves around. she did not know what the cause of the lump along bra line. went to have mammogram and ultrasound. the only thing they said was that the lumps where solid, and i am to get a needle biopsy. i am somewhat relieved that it moves around, has not gotten any bigger. any one have any opinions if this could not benign or cancer, so much anxiety it is freaking me out. also 8 months ago had mammogram and ultrasound and found nothing, why would this all happen right when i got a cold., any advice would help. thank you