Can you have multiple myeloma and breast cancer at the same time?

I was diagnosed with multiple myeloma almost 6 years ago. Had a SCT in. 2021. Was only in partial remission for 6 months. Have been thru 6 lines of treatment and am currently taking Pomalyst 2mg for 21 days and then off to 5 days and repeat. Also getting Emplisiti IV once a month. As of April of this year PET scan showed no evidence of active myeloma!! Am I thrilled beyond words?? Yes, I am. However I had a routine mammogram this past week that showed a mass in the right breast. So now it’s an ultrasound of the right breast & biopsy this coming Thursday. I just can’t believe that I might have breast cancer and multiple myeloma! My 32 year old son is not handling any of this very well. In fact he has told me that the main reason that I have cancer is because I am not emotionally able to accept it! I haven’t been able to talk to him since he told me that. He has stopped calling me and won’t come to the house to visit. So all of the above issues are definitely affecting my mental health. I do give thanks for my husband, he has been a rock! Hopefully the news will be good next week and I won’t have that worry. Saying prayers and praying for the best. So sorry for the long post, but I had to get it off my chest.