Welcome to HCM.
From your problem it seems that you have either multiple sebaceous cysts or lipomas
on your back. Now for the painful swelling on the spine may be due to secondary infection in these swelling causing tension and compression on underlying cutaneous nerves. This is a common condition, especially in sebaceous cysts where infection is quite common. You should meet a surgeon who can relieve you from the problem within few minutes by excision of the swelling.
Get well soon.
Dr Sanjay K Kanodia