Some Good Advice Here
Coolcat - With all due respect to the many wonderful MPAs out there, if your back pain is caused by some underlying spinal injury whether you're aware of the injury or not, the wrong kind of massage pressure CAN further damage the inflamed area. This applies to RMTs and chiros as well, as was stated.
Simply getting what is usually a nice rub down could be damaging. I personally suffered from sciatica - spinal nerve pinch - a number of years ago. Treatment was muscle relaxants, RMT to relieve pressure and then she referred me onto a physiotherapist.
I once saw an MPA who was studying to be an RMT so she knew exactly what she was doing medically. But those Ladies are far and few between.
Now, if by back pain you mean a sore shoulder or something then, that might be different. But maybe not. It is wise advice to get yourself to your doctor.