A bra is not meant to uncomfortable. If it is, it's the wrong size or the wrong style. Finding the correct size and style bra is difficult but not impossible. I spent many years wearing the wrong size. Having breasts helps also. Bras are not designed to fit the average male chest. I did not find a comfortable bra until I got proper weighted breast forms. The weight of the forms holds the bra down and it does not have to be so tight. Also price is a consideration. The more it costs, the more comfortable it is likely to be. Of course this isn't a hard and fast rule, but there is a lot of truth in it. A cheap bra is gonna feel cheap. My wife once bought a bra for $125. I was appalled, but she said it was the most comfortable bra she had ever worn. I find that with the proper bra I often can forget I have it on.
Keep trying. Use the size charts only as a starting point. You can always take a bra back for exchange if for some reason you can't try it on in the store. There are literally hundreds and hundreds of bras out there. There's one that's right for you. Think of all the fun you can have looking for it!!
Lovies,
Stephenie