Newbie, Few Wheel questions.

Hey everyone, I have just recently got into cycling and am confused about something. I ride a Giant OCR limited carbon with Xero Lite XSR-3 wheels. On climbs, my front rim is rubbing brake pad. A bike mechanic told me that this is actually the bike flexing and not the wheel-dont know if i buy that though. I weigh in at 180. I am thinking these wheels my be too flexy for me and my size, they are 20f/24r spoke count with a 2000g weight. I cant find much about these wheels on the internet. Do the wheels sound flexy or could it be the bike? The wheels also suck on climbs. Also, what kind of maintenance should I expect for a wheelset? Is there any type of preventative maintenance you are supposed to do? Tighten spokes or check for true every X amount of miles? Thanks!!!!!

I had the same problem with my stock rims. I got some new/stiffer rims and the problem is much better and I am sitting at 240ish