I Had My Left Breast Removed In 2008. The Doctor

I had my left breast removed in 2008. The doctor went in the lymp node and found nothing abnormal.i did plastic surgery implant on the left breast. The plastic surgery coupled with the breast removal and lymph node check resulted in loose skin at my upper back close to underneath the left arm.In 2015 i had surgery on the left arm due to multiple myeloma. i received radiation to the arm prior to surgery.
Due to multple myeloma i was in treatment of dexamethasome, revlimid and velcade. I started noticing tingling of my left upper back and started wondering which of all the above procedures messed up that area.
The oncologist said maybe it is shingles. i was placed on Acyclovir for 3 months but felt no relief. I have no rash in that area, no pain, no headaches only the tingling. I thought maybe the brazier rubs in the scar area around the breast and the upper back may be causing this,but it happens even without wearing a bra.
What could this be? what medication will relief this.I am scared. I am thinking of removing the implant on the left breast,and leave the breast flat maybe the implant is pulling the muscle in the upper back.