Common problem under treatment for some is joint pain. Maybe your doctor will prescribe low dose Lortab or such for relief. If it's due to swelling, ask your doctor about Ibuprofen 800mg pills. My Gastro said I can take 3 per day with Hep C. Best to get an opinion by your doctor. Jacuzzi will help, although it's temporary relief. Good luck...
I am on my 11 week, I also have developed a back pain, however just at my second month, where I wake up at night in deep pain, can not find a position to sleep and in fact, I have not really slept at all lately due to this and some serious throat canker problems.
For the back, I am seeing a chiropractor, this week will be my 4 session and it has worsen until the 2 session and now it is getting much better.
If you do decide to see a chiropractor, advise him that you are in interferon and treatment, he will take a different approach, they are used to patients like us.
Good luck and advise if you find help.
Happy new year,