How long after a big toe fusion surgery does it take for the pain to go away in the toe?

It takes a year : Or so to fully recover from any major injury or surgery. Basic healing from a fusion takes about 2 months, but there is often still some "nuisance" aches and pains thereafter, gradually subsiding over several more months.

After bone heals: Usually, once the bones are healed (or fused together) the pain should be subsiding. If this is not the case, then you need to let your surgeon evaluate the problem.