Hello welcome to this forum. I hope you are okay, it must be difficult to feel something that is not normal for you.

I should start by saying that most breast lumps are harmless.

However, it is very important to book an appointment with your GP to get it checked out. It can help to take a trusted family member with you and write down what you want to say or ask beforehand.

I think it will be useful to mention that your period hasn't started yet, your weight and the problem with your heart. It must be hard to be dealing with these, especially at such a young age.