Are the knots in the skin or deeper in the muscle?
You can have faschia swelling on the muscles in the back but I don't know of another name except faschitis.
Also if they are deep in the skin they could be lipomas!
I believe the term you are looking for is myofascial trigger points. A good physical therapist can actually find them in your muscles and apply pressure (hurts like the dickens while they are doing it) but it does relieve the pain.
Pamolar is an antidepressant that is used along with other therapies to improve pain of all types. Today we often do trigger point injections and physical therapy along with pain medication and Pamolar or amitriptyline or other antidepressants to relieve the pain. An orthopedist or rheumatologist would be the specialist to see.
The same to you! Hope you get those trigger points taken care of.