Bras help to keep a woman's chest supported and comfortable but straps that are too tight or too close can cause discomfort. Bra straps are adjustable and those that are too long can be easily tightened for a better fit.
Stand in front of a mirror wearing only the bra on your upper body. The mirror will help you to see if your bra strap is correctly lined up.
Slide a finger between a bra strap and your shoulder. If you have a lot of wiggle room and can pull the bra strap up away from your body then the strap is too loose. Or if the strap automatically falls down and you have to push it back up then it is too loose.
If your finger cannot fit under the strap and it hurts to try then the strap is too tight.
Feel the back of the strap with your hand to check for the small adjustable plastic or metal clasp.
Feel the middle section of the clasp and pull up on the material in the middle. The bra strap will tighten and the clasp will move up on the strap. Pull the material until bra strap feels comfortable on your shoulder.
Place your finger under the strap again to ensure that the strap is now short enough to stay in place. Repeat the process with the other strap.
Bras can change their shape over time and the strap can lengthen due to the elastic getting weaker. Replace your bra if it is old and the elastic on the strap is stretched.