Usually painful lumps are not indicative of breast cancer…It could be anything such as a cyst, an infection or a swollen lymph node. Nonetheless a lump near the axilla area is always concerning and over the internet it is difficult to estimate what it could be without proper investigation. Please have this seen by your doctor and undergo work up such as mammogram and ultrasound. This will be much more reassuring to you and will certainly reduce your stress. Waiting 2 months until you see your doctor is not very far off but I think it’s better if you could contact a Breast clinic or a nearby hospital for a breast exam, just to make sure things are fine.