sudden severe back pain comes and goes

Twice within the last 12 hours I've had sudden back pain that has started in my mid-back along my spine and spread out from there. It's hard to breathe. The first time it happened, I was at work sitting down. It went away in 5 minutes. This time, it awoke me from sleep and lasted for 15 minutes. I try stretching, deep breathing, but nothing relieves the pain other than time.

A few other details... I've had severe asthma problems recently. Lots and lots of coughing, which started three weeks ago. Things have been under control for about a week now with some new meds from my doctor, including Aerobid and a new drug called Zyflo. During those couple weeks of coughing, I had really bad back and neck problems (presumably from the excessive and violent coughing) - stiffness, pain that was always present across my whole back, had difficulty finding a comfortable position lying down.

I have never had any chronic back problems. It makes me wonder if the problems are related to the coughing (did I throw something out of place? If so, why has the pain gone away entirely except for today when it flared up twice?), to the new medication I'm on, or to something totally unrelated, like a virus? Other meds I'm on, that I've been on for years, include Alegra-D and Singulair.

[midnitemoon]

Maybe a kidney stone?  That usually starts in the middle to upper back area and is sudden and severe.  Also it can come and go in waves and without warning.