Well depending on your age, the likely diagnosis of a breast lump would change. However any breast lump should be investigated. It is great to hear that you had a mammogram done. So lets jump to conclusions in a hurry. Beside breast cancer there are other causes of small breast lump and most of them are benign and not cancerous.
Only the mammogram would be conclusive and I will be in a position to help you once I get the report. Also if you have any additional symptoms like nipple discharge, puckering of the skin, lymph gland swelling in the armpits, fever or pain, please do let me know.
If you have any further queries do get in touch with me.