Hi,Dear thanks for the query to HCM virtual clinic.
I studied your query in full details updated from you.I understood your health concerns.
Based on your query data, In my opinion ,You seem to suffer from Sebaceous Cysts,which are more common on the back due to friction and nonhandling of the
boils,by location.
Dear These are benign lumps,which are not Cancerous.These lumps are not harmful.But are caused by,retention of the obstructed sebaceous glands of the hairfollicles.
If you are worried by its recent growth,You could ask for its removal if it worries or troubles you by its size or by its growth.
Thus
Second opinion form Surgeon and USG of the lump would resolve this issue.
Hope this would resolve your query and worry.
Welcome for any further query in this regard to ME.I would love to help you out.
Awaiting for any further query.
Wish you fast recovery from this intriguing health problem.
Have a Good Day.
Dr.Savaskar M.N.
M.S.Genl-CVTS -Senior Surgical Consultant