I can't control my erections and i am 19, why is this?

Normal: Men your age (assuming 19 years old and not 45 years old) can have several hundred erections a day. It has to do with your hormones and your age. Unless the erections last unusually long (> 1-2 hours each) then this is not a medical problem.

Nobody can: If you're physically healthy, you'll get at least a dozen daily at your age. It's a good thing, and there's nothing "spiritual" about trying to suppress this gift that will make you able to receive and give love and perhaps eventually be a father. I trust you plan to love responsibly. Learn how to keep them from being obvious, and enjoy who you are.