How long after BA can I wax my underarms?

Waxing after a breast augmentation probably is OK. I am not really sure of the problem that you described.  Best of luck.

Although as a man it's hard for me to ever understand the concept of putting hot wax on my body and ripping off the hair...This may be a painful thing to do and you may feel that waxing was limited due to not raising your arms fully...but I can't really think of any reason why it would be contraindicated unless, obviously, the approach for your augmentation was trans-axillary.  I'm not sure if the procedure causes people to tighten the underlying pectoralis muscle in reaction- this may be undesireable.  Logic would tell me that if you just had surgery then wait a little bit before doing anything like this...but I can't think of any real contraindication.