Hi and welcome to HCM. Thank you for your query.
No,this isnt cancer, this is fibroid
and fibroid is benign tumour. It is hard to say does this cause your symptoms but you should find the cause of your period abnormality. It can be hormonal
imbalance or ovarian pathology. Fibroid can cause bleeding and pain if become enlarged enough. YOu are in premenopasal age and it can be expected to have such difficulties. You just need to do frequent check up and consider hormonal therapy. Wish you good health.