Itching and stinging on right breast

Hello i'm Katie and i'm 12 years old and when i went to the beach around 2 years ago and when i was in the water my right boob was itching and stinging and then when i got home and took off my swim suit i had these small red tiny but sill noticeable 2 to 3 bumps on my one breast and those bumps have been there ever since... And i have no idea what they are but i think maybe something in the water bit me, or too much salt water, or acne, or something but it hasn't gone away can you please help me figure out what this is ? thank you for your time :]