Anyone deal with shortness of breath after quitting?

I imagine it's from 8 long years of heavy weed smoking and countless blunts, but I'm just curious if it ever gets better. I never noticed it when I was smoking weed, but now that I've been sober for almost 2 weeks, I'm definitely more aware of it, especially if I don't sleep well the night before. I'm getting out and walking and running every day, though, to build up my lungs again, 15k steps or more every day. I imagine it'll take weeks or months to get back to normal. I'm not wheezing, but I notice I can't breathe quite as deeply as I'd like.

I imagine that's my lungs/body reacting to not having any new THC coming into the system and now my body's trying to heal. When I went to the doctor recently they did check my breathing and my bloodwork and everything came back A-OK, so I imagine everything will get back to normal eventually, yeah? Any ex-smokers got some words of wisdom? I am also cutting out caffeine rather abruptly, not sure if that factors in...