I have braces bcoz of spaces between my front teeth but suddenly d gums between it swell & it hurts when I brush it. I regularly brush & use mouthwash?

Orthodontist. Please speak to your orthodontist. As discussed in my prior answer to a similar post you made, since there is less space between your teeth, the gum tissue has been compressed in that area. Over time things should be fine. Great oral hygiene will help.
Ortho\gum issue. I recommend that you consult with your general dentist to e-valuate your oral hygiene and orthodontic appliances. Have him\her discuss with you how best to keep those areas clean and uate both what brush\floss\oral hygiene products you are using and how you use them.