Would lower back/spine pain be due to shingles as have blister rash on stomach?

Shingles pain: It sure can, but this is not something to ask on the internet of you have an active infection. Go see your dermatologist immediately.

Shingles: Herpes zoster, called shingles, is an infection of a nerve by the chicken pox virus. When you had chicken pox as a child, the virus was in every part of your body, but some virus stayed alive in a nerve, deep inside, and in many people the virus becomes active, usually when we are old, and causes painful blisters, in a line, and only on one side of the body. If you have this, then you have it.

Could be: With a painful rash following a specific nerve distribution pattern, you likely have shingles outbreak. If you have an outbreak, please stay away from anyone who has never had chicken pox, until rash resolves. Go see your doctor for proper diagnosis and treatment. Your back pain may be related to the rash, or might be unrelated.