I would recommend that you have this checked out. The good news is that nothing hurts, but I think blood in the urine in a young, otherwise healthy male should always be investigated by your doctor
There are several potential causes.
In young men, an infection with a sexually transmitted infection might cause some irritation of the urethra. Typically, the symptoms would include discharge from the penis or burning with urination, but they could also conceivably include small amounts of blood. A simple urine test will be able to rule out sexually transmitted infections and urinary infections.
It will also be necessary to make sure that your kidney function is ok. Make sure to tell your doctor if their is any one in your family who has suffered from kidney problems or problems with deafness, and also let them know if you have ever had this before. There are several kidney disease that need to be ruled out, including IgA nephropathy and Alport's disease, and your doctor will probably want to send some simple blood and urine tests to do this.
Start by setting up a visit with your primary care doctor
. If the symptoms continue they will be able to coordinate any further workup or specialist visits you might need.