Why does my mom yell for nothing?

There are many reasons why she may be yelling. She could be stressed out; stress can unfortunately cause us to lash out to those we care about. There's also the possibility that she feels unhappy or upset, and as a result she releases this by shouting. Or, she could genuinely have believed that something happened that warranted certain behaviour. If you're still unsure, it could perhaps be a good idea to delicately ask her why she reacts in certain ways. Sometimes, we never know why another person acts the way they do unless we ask. However, she may explain her actions at some point without you asking.

Most likely she is feeling alot of anger and emotional pain within herself. This has nothing to do with you but her own internal personal issues. When she gets irritated by small things and yells its just because she is overflowing with her own emotions and this is her automatic way of releasing it. She may not even mean to yell it just comes out that way. Please remember that it is her own frustrations and has nothing to do with you. If she yells at you for whatever reason you must know that it is not your fault. My mum uses to yell at me so much for not closing my cupboard door in my room. When I look back at it now I realise it wasn't about the cupboard door it was just a trigger for her to release some of her pain she was holding onto as she was not releasing it in other healthier more productive ways as she didn't know how.

I am so sorry this is happening to you, this is to let you know that she is a human first then a mom. Every human has their good and bad days. Maybe your mom is upset about something deep down that is troubling her and she has no one to talk to and let her heart out. Maybe she is converting this into frustration and yelling at you. You can try to give her some space, then go to her room when she is calm, talk to her, and try to be there for her and resolve the issue in your own capacity, if possible.