I feel a lump in my breast.

Please know that it is not possible to definitively determine what a lump in the breast is, by palpation only. There are numerous things it can be such as – fat, dense tissue, a cyst, fibroadenoma, papilloma, area of fibrosis, lymph nodes, a vessel, coarse calcification etc.
The best thing to do is to get in touch with your primary care physician to get checked. They will likely give you a requisition for imaging which will include either an Ultrasound (US) or an Ultrasound and a mammogram. Please know that it is not possible to definitively determine what a lump in the breast is, by palpation only.
While it is most likely to not be a cancer, do not assume so until you have had some form of imaging.
If you do not have a primary care physician, please go to a walk-in clinic to get assessed.