Ever since my friend told me something, I have decided that I want to tell someone else.
Seriously? Why do you have to tell someone else a secret?
They told me it was a secret but I just hate keeping secrets.
I get that it can be hard to hold it in but your friend confided in you. They were willing to tell you a secret and trusted you to keep it so you should. Make sure you keep secrets to yourself or you risk losing the trust of the person who told you them.
Lying is fine.
No, lying is wrong and so is telling other people's secrets and if you do this you'll never be trusted with another one. Do you want to be known as the person who spills out everyone's private affairs?