When I was "corporate man" I spent quite a few business trip evenings in Stockholm - great city.
Start the evening at the Opera (Opera House?) cafe / restaurant and just people watch over a couple of beers.
For jazz get a taxi over to Stampen in the old town - it's where the "Jazz at the Pawnshop" albums were recorded. Nice atmosphere downstairs - have a few beers - get asked to dance by young ladies - there are worse ways to spend an evening.
I know there are other rock / classic venues but I didn't go looking.
You'll find that the cab drivers and hotel concierges know what's happening.
Good luck - and remember it's expensive over there.
Regards
Graeme