Yes, 10 days should be fine, especially as you have symptoms.
I don't know all your symptoms, but burning in your urethra can be caused by a lot of things. It can be from something causing irritation, or dehydration, or a lot of other things - https://www.healthline.com/health/pain-in-urethra
Not knowing your other symptoms, it's hard to pinpoint anything. You can always test again in a week or so, and see if anything appears.
Had it been at least an hour since your last urination when you tested? Did you follow the instructions exactly? I imagine they ask for first catch urine, and not midstream. Your first urine usually has more bacteria in it, making things easier to find.
If any of that didn't happen, maybe you'll want to retake the tests.