STYLETHREAD -- LET'S TALK SHOP!

I am experiencing some back pain lately (upper back).
I think the main reason I isthat I slouch when sitting, and the fact that I sit all "bent on the side" at home while watching movies is not helping either.
On top of that, my favourite workout is running, which is great but doesn't do anything for my back.
I do stretching and back exercises (not as much as I feel I should), but I'd like to try massage too, like once a month or so.

What kind of massage would you recommend? Of course I am gonna talk about that with the massage therapist too, but just wanted to hear from your experience.
Other q: should I tip the therapist, and how much?

tia!