I have toothbrush abrasion, can i wear a retainer or braces?

Yes: On the abrasion (or abfraction) lesion on the neck of the tteth, we can place a white bonding matrial( composite resin filling) and then you may have regular braces or invisalign, etc.

Yes: I'm assuming you're talking about abrasion of the root surfaces of your teeth where the root "dentin" becomes exposed. I would be very careful about expanding your smile too much, the potential for increased root sensitivity, increased bite forces that might worsen the condition, etc. This is a job for your dentist or orthodontist to watch out for, though. Other that that, you should be fine.

Issues?: I'm not sure of your specific situation and what treatment you have had or are contemplating? Are you trying to address the tooth brush abrasion issue? Or wanting\needing orthodontic treatment? You can have orthodontic treatment and afterwards a retainer with tba. Ortho treatment\retainer won't address the tba issue. Discuss all these issues, relevance and what's best for you with your own denti.