My mom is always in pain, she has bad knees, hips and has difficulty walking, she will not go to the doctor or have anything looked into, she doesn't want to have any hip or knee surgery. So unfortunately she spends her says constantly in pain, when you go to offer your help to her you usually get snapped at and she refuses your help, but then will walk around in front of you in major pain, so you feel guilty for not helping her with the help she has refused. Most of the time she is always snapping or yelling at my dad and myself, we deal with this daily, it is hard to deal with and it gets me down a lot, but I bite my tongue and let it happen. Today I come home and was looking for something in the freezer, my mom goes, don't stand there with the freezer open, I had it open for like 30 seconds, so I said to her, I have barely had it open and you are acting like I have been standing there for 10 mins. I look at her and she is looking the other way trying not to cry, which of course makes me a) mad because she is always snapping at me and the one time I say something back, she acts like I am slapped her down and then b) guilty because I got mad and snapped at her. It is just hard to keep at level head sometimes when you are constantly being snipped at and you cannot say anything back and when you finally do you are the bad guy. I love my mom and I know she is in constant pain and this has affected her personality, so I feel so guilty when I get mad and upset with her. I am sure there are other people out there that can understand my post and maybe have advice on how to deal with this without me going crazy!
Then calmly explain that you feel you can't do anything right, you don't try or want to upset her but little things you do create that effect, etc. So, how can the two of you work together to resolve this? She'll probably cry. Hug her and reassure her that you want to find a solution that works best for all of you.
Don't expect answers; let the talk "sink in", and wait for her to raise the issue again.
This may not work, but it's worth a try. I think she's angry at her situation and is so angry and frustrated that she won't even attempt to address the pain issues.
There also comes a point at which there's nothing you can do to change her attitude, and that's something to remember as well.