a quick search turns up that the nicotine may be aggravating "cytokines" in your lower back[1]
a compound in blueberries and lentils, myricetin, may alleviate such pain[1] and lower cytokine levels[2]. There may be more powerful examples in recent literature, this is just one dredged up through 10 years of Firefox bookmarks 
i remember hearing about a novel natural treatment that could (somewhat) heal motor nerves after blunt injury. not sure, but probably buried in one of Flex's threads somewhere. IIRC, it was something weird like ALCAR + horny goat weed? may be worth examining.
So dietary control over cytokines and inflammation are one avenue to pursue, in addition to the presumed yoga and tea drinking.
As for alternative to nicotine? Research is still emerging on ADHD-subtypes, and treatment seems to depend on the individual. for example though the ADHD-C group reports greater absitence among the ritalin than the placebo group, on the other hand the ADHD-PI group given ritalin consumes even more nicotine, suggesting a positive feedback loop[1]
but what can we conclude? Possibly that you are the predominantly inattentive subtype, that you regrettably have a greater potential for drug dependency, and that your symptoms are partly nicotinic in origin.
Things that may help? Maybe instead of NE, DA look to α4β2 and α7?
- Ginkgo with its bisabolol antagonizing α7-nicotinic sites[1],
- red ginseng has been effective for me, and research suggests it has some active at mutated nicotine sites[2],
- ashwagandha with a mild agonizing effect[3]
At the end of it, ADHD is a daily struggle, lots of well-to-do people fail school because of it.
You have to make an effort to focus, and accept the fact that some days you won't do it very well. Make the most of your creative bursts, and don't overly-dramatize your wander-y moments. Find an individual approach and be willing to adapt it.
