Bit of an un-conventional TRP question here.

I find it hard to finish any sentence without running out of breath, and sort of having to force my words out with no air in my lungs. I'm not fat or anything, and I hit the gym 3 times a week. no cardio though.

I speculate it is down to my posture. Ultimately, I want to improve my breathing so I don't keep getting out of breath while talking. I spend lots of time sat in a chair. I also have weak abs, from years of gaming my tits off long into the night.

I feel like I walk with good posture, although my shoulders round forward a bit.

My question is, can anyone pinpoint my problem? Why i sort of run out of air while talking? And what should I do to correct it, and has anyone else dealt with this?