Crye for it.

When it comes to buying shirts that fit, sometimes it can prove difficult if you don't know what you're looking for. If you are a beginner and you are looking to improve upon your style, but don't know where to start then this is a great spot.
These guys give you an abundance of options that are easy to understand. Just take a look at the sizing chart to see exactly what I mean.
The price is in the right spot to where it wont break the bank to get a few at a time. I plan on buying from Hugh & Crye often. I think you should as well.