Janet, it is very normal to be sore a day or two after an adjustment, esp if the problems are severe. Drinking lots of non-caffeine/non-soda liquids really helps as it can flush out the byproducts of the muscle spasms out of your system. If you have fibro, often the 2nd day after is the absolute most awful time.
Do you ever get a massage? Can you get your reg or your pain doctor to rx phys therapy massages? One of the best chiro's I have known kept 5 massage therapists on his staff, not all full time or there at the same time, because he wanted patients to come in and have a massage before he worked on them. Why? When the muscles are more relaxed, the adjustments are less painful, less difficult to do (so you get more done) AND they work better and last longer. The better/longer is NOT just his or my opinion. It is written up in reputable journals - I used to read them in the waiting room because the other magazines were more boring. Even before reading about this, I noticed that chiro treatment was more effective after a massage.
As for the length of your legs, having one leg off by millimeters can make a HUGE difference and you might NEVER know unless a doctor or chiro checks. My dad has one leg that is 5 mm (half a centimeter) longer than the other. He had lifelong pain in his legs and back. Having a little thing under the heel of his shorter leg made an amazing difference in his problems. It was NOT immediate because his muscles spent many decades adjusting to that difference and had to become accustomed to the change. About five or six weeks out he was able to walk more, came home from work with more energy, even was willing to go and do things after work that before he was just too tired and sore to do. it didn't solve all his problems, but it made a very significant difference. Over the years he has occasionally forgotten it, or thought he didn't need it any longer. My mom's reaction is not pleasant when he does this, not any more pleasant than when he forgets his blood pressure or other medications. Mostly because he ends up in a lot more pain and pesters her to rub his legs and back more. She doesn't mind doing it usually, but when he causes the pain by being an idiot, well, she isn't patient or nice about that.