I had a bypass on 17th Oct 2013... have lost 16st since...
when I woke up from surgery (had mine at St Richard's, Chichester) and to be honest I actually didnt think they had operated (much to the amusement of the nurses!). Woke up bright and alert, no pain whatsoever... had a little (very slight) tightness in chest (wind!), but a dull ache not sharp pain. I expected to be on a drip/drain... and in agony etc...
I was up and around within hours - walking up and down to try and expel the wind!
I found the staff to be SO attentive and aware of pain thresholds etc and the ladies I was in hospital with were in a lot of discomfort, so the nurses were more attentive to them...
Wish you well for a successful op.