I'm a lay-expert on this stuff, unfortunately, Achilles.
Start with your spine, and an MD. They'll point you to physical therapy and/or massage, if appropriate.
Chiro failed for me. It may help as a preventative or add-on. I wouldn't start there. JMO.
A spine/pain mgt. doc will often offer injections into the laminar area adjacent to the spinal cord; that's a
steroid shot adjacent to the area of inflammation. Don't be fooled; maybe your shoulder is killing you, for example, BUT the inflammation that causes the pain could be 8-10 in. away, by your spine. There are MANY spinal conditions (degenerative disk disease, extruded disk, bone spurs, stenosis, etc.) that can cause bad, persistent nerve pain in the back area.
Benoy Benny, MD has a Spine/Sports Med practice (offices in Galleria, Sugarland). He does a lot of injections, but you could see him for a consult. You need, IMO, an MRI at minimum for a good diagnosis.
Hopefully, you have muscle pain that just needs "topical" work (massage, etc.), but, instead of messing around like I did....I'd go straight to an MD and inquire about an MRI.
PS- Dr. Benny was previously at Baylor. You could also call their "Physical Medicine" Dept. for an appointment with another Doc...I had good luck w/Baylor (location: Baylor Clinic - Med Ctr).
caveat: I'm not a doc...