Do you have any pain in your kidney area? Or in your lower back?
I don't know much about urine stream but if its accompanied by some form of discomfort it would be worth talking to the doctor about it as it could be a kidney stone in the early stages.
As for ejaculating, that sounds like "premature ejacualation". I think alot of guys go thru that in their teen years. Its like you just get so excited that you can't help but ejaculate as soon as you get an erection. That should get better with time and experience.