Hi lisarea425
It sounds like you have a complex multifactorial problem and seeking a solution that may address that the multifactorial nature of your problem may be helpful. My guess is that whatever is going on structurally, you probably have a number of changes in the way your muscles work that affect your posture which tends to happen over time with long standing musculoskeletal issues. In addition you probably have a chronic pain problem and this may also need addressing
There are different types of chiropractors out there but the main stay of chiropractic is a particular type of manipulation that involves what is called high velocity thrusts. Other practitioners also use these techniques but chiropractic makes a very big deal of them. The traditional theory is that these manipulations reduce “subluxations”, which are supposedly malalignments of the spine, and thereby promote health. This is quite erroneous – subluxations are not the basis of pain of musculoskeletal pain in most cases. Manipulation has been shown to be ineffective in treating chronic musculoskeletal pain. There is some evidence that such manipulations may help in the acute low back pain (pain for less than 3 months) but the effect is only immediate and short term and needs to be combined with other treatments. The beneficial effect is probably nothing to do with the mechanics of the treatment. Here is a site that takes a skeptical look at chiropractic:
http://www.chirobase.org/
Two suggestions I would make is have you had a really good postural assessment? A thorough look at how your muscles are working i.e. and how this is affecting your posture and movement – this might be worthwhile. Physios are often trained in a different approaches to addressing posture. Once such system is advocated by Shirley Sahrmann of the University of Washington, St Louis – so you could ask if your physio is trained in this. The approach looks at how your muscles are working in relation to your posture and movement, identifying muscles that are weak, muscles that are tight and muscles that are overdeveloped. You are then given a number of exercises that can be progressed to meet your needs. Some Pilates practitioners are very skilled in this way – although as it is so popular there is probably a lot of hum drum pilates out there. There area also a number of postural awareness systems that can be helpful – such as the Feldenkrais Method or the Alexander Method. The Alexander Method has been shown to be very effective in a recent UK trial of sufferers of low back pain. With a lot of these methods you will find some people get a lot out of it and some don't. It might be a case of trying something out for a while and if it helps great, otherwise move on to something else.
You may need some help with coping with chronic pain. Your nervous system undergoes changes over time and processes pain differently. This means that the perception of pain can become a problem in itself. There is practical advice and help you can get with this.
Sorry this is rather long but I guess I wanted to say there are a lot of options to explore, many that might be better choices than chiropractic manipulation at this stage. All the best with getting further help.