dear Rubyellen,
It is hard to say without an exam. You could have scarred veins. you could have phlebitis. It could be that some of the chemotherapy went into the tissue around the veins and is causing a tissue reaction. It is least likely to be blood clots given the location.
usually elevation and warm soaks on the arms is helpful. If there is any redness, addition of antibiotics to treat possible infection is reasonable.
best wishes
Continued. The pain in armpit, breast and chest in continual through the three weeks. I also have very swollen and painful lymph nodes in groin which physician says are reactionary from hysteectomy on 11/18..