Do steroid injections or nsaids affect sperm count?

No major effects. Assuming you're talking about 'regular' prescription corticosteroids like triamcinolone (kenalog) these have little to no effect on sperm - unlike Anabolic steroids like testosterone or dianabol, which can cause major reductions in sperm count. Some studies indicate that heavy NSAID use, including aspirin, may affect sperm motility and morphology as well.
Not significant. Nsaids are not known to have significant adverse effect of sperm count, but high dose of steroids can. Often injections such as in joint or epidural etc..Are of relatively short-lived time and thus effect on sperm count is minimal, if any. High doses and long-term use can suppress sperm production, among many other effects. Sperm analysis will tell. Consult doc if u have trouble. Good luck.