Painful lump r armpit 49 f dental hygienist general aching r arm numb fingers r wrist neck bicep thumb middle & ring joint swelling on & off 3-4 month?

Cervical pressure. This could be related to pressure on your cervical vertebrae , if the nerve is under pressure it could send numbing sensation into your arms and fingers, it is affecting you r side. You need to see an orthopedic surgeon and get it diagnosed properly. Hope you get better.
Need evaluation. You need an examination by a hand specialist or neurologist to make the correct diagnosis.