Brand doesn't mean a thing if the fit isn't there. Just go to TJ max for now and get some "athletic" or "slim" cut button downs in neutral light colors. Even if you are not athletic or slim they will probably give you a more flattering fit. Read the guide I posed above.
If you insist on sticking to Polo shirts, TJ Max has also been stocking Calloway golf shirts lately. They have, by far, the best fit. Most others are very baggy and straight cut from the underarms to the waist. These are what I generally wear when I visit a factory floor, I picked up a bunch of them for $19 ea.; hell of a lot better than the pro shop is asking at the club.