For the constipation, gentler is better. Bisacodyl, a generic laxative, works well -- no more than 5-10 mg, and be sure there's a toilet nearby for the next 24 hours.
Even gentler, but slower, docusate sodium stool softener and gentle laxative.
For daily regularity and bicycling fuel, my usual breakfast is a banana sliced over any decent cereal and yogurt rather than milk.
Regarding pain relief, if you're especially sensitive to ordinary stuff like cyclobenzaprine, try over the counter stuff with magnesium salicylate -- Doan's pills or generics. Very commonly found in truck stops, grocery stores, pharmacies. It's just an ordinary NSAID, but works better for me than aspirin.
While I've had good experiences with a couple of chiropractors, that's mostly because of the massage and consequent improvements in circulation and reduction of swelling. There's nothing magical about chiropractic treatment, and aligning joints is mostly hocus pocus -- the alignment vanishes as soon as you move again. But some chiropractors have great hands and if it feels good, do it.
Long term, the treatments to relieve spinal stenosis probably works as well as anything. Worked for my mom and dad and several other folks I know, and it's minimally invasive.