Hello,
Thanks for posting your query.
The small painful lump on the breast while taking hormone therapy can be due to a small infection or a malignant lesion.
The possible causes for your symptoms can be-
1. Fibro cystic disease of the breast: sometimes small noncancerous lumps will occur in the breast usually because of hormonal influence.
Sometimes lumps may not be felt.
Swelling, tenderness of the breast, itchy nipples can be seen in this.

2. Mastitis :
It is characterized by pain, swelling, redness of the breast in case of presence of breast abscess fever can also be seen.

3. Presence of lumps(fibroadenoma) or cysts in the breast.

Now you once visit local general surgeon and undergo checkup if needed go for mammogram which will help in diagnosing the cause.
Depending on the result you can take the treatment.

Hope this answers your query. I will be glad to answer the follow up queries that you have.
Please accept my answer in case you do not have further queries.
Wishing you good health.
Regards.
Dr. Rakhi Tayal.

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