I’m a guy and I have small breasts.
Super awkward, but SUPER NORMAL! Almost 65% of males have slight breast development (called “gynecomastia”) during puberty. It’s usually at its worst around 13 - 14 years old. Breast tissue can be tender and one side is usually bigger than the other (same for females).
What to do about it? Most males will outgrow this in about a year or so. However, if the breasts are large and persist past a year, chat with your doctor. There are a few additional things (besides normal puberty) that can cause gynecomastia.