2 days post-op breast aug- is it ok to have a large bruise above my sternum (deep blue, red slightly raised splotches)? Still in lots of pain. Thanks

Call your surgeon. While I am happy to participate in health tap and be able to answer general plastic surgery questions, there are often questions here that start "i am so many days post op and ..." as a surgeon, i would much rather my patients call me with a question they think may be "stupid" and it turn out to be nothing rather than miss a significant complication because they posted it online. Call the doctor.
Most likely Yes. Sounds pretty normal. Obviously without seeing you it's impossible to know for sure. Call your surgeon if you have any questions.
Maybe, maybe not... It is not uncommon to have bruising after a breast augmentation, but a large bruise above the sternum (i am assuming in the midline) would be unusual. Check with your surgeon.