Electric static new problem
Related.  Or at least, you shouldn't take the chance that it's not.   

Turn the main breaker off to the entire house and see if it still happens.  That will be the final word on the subject of whether it is electrical related or not.  I suspect it is.  

Other than that, don't test it.  Don't tease the dragon.  What feels like a minor pinprick when the rest of you is well insulated from anything metal, can become lethal current flow if you get between something hot and something grounded.  

I would not be looking at breakers, I'd be looking at the grounds and neutrals.  

A possible cause is the A/C guy misusing a ground as a neutral.  This can easily combine with another type of failure to put dangerous voltage on every ground in the house, i.e. Every switch cover plate, all metal conduit, dryer or stove chassis, even the circuit breaker panel itself.  The "other type of failure" might be the original problem.