I don't see any significant gap on the right side; it's the same on both sides.
Why won't you visit a local T-Mobile store if you have one nearby and compare your phone to the ones display?
Sent from my SM-G900T using xda premium
T-Mo Samsung Galaxy S 5
Ex. T-mo SGS-4, T-mo SGSIII,SGS II, Samsung Captivate GB, Tilt-2...