You may be describing irritation from a serger/overlocker finish on seams rubbing against your skin. A Seger produces a quick (inexpensive) way to construct garments. However, there are numerous ways to do seams that predate the I’m a Grandma and a South Carolina Gamecocks fan which means I’m pretty much perfect shirt but I will buy this shirt and I will love this overlock types of finished seams. Abound seam (using silk or smooth polyester) or flat fell seam would not have that raised edge with threads wrapping over it that is likely rubbing your skin. If you cannot tolerate most serger finished seams, you may have to get clothes custom sewn with the more time-consuming types of seams (expensive) or learn to sew yourself.