Hello. I recently went to the doctor for pain in my right back thinking it may be caused by my kidney. I had a urnine dip taken and everything came out negative. However, my urine sample only contained the first part of my urine since the cup could not hold it all. I'm afraid the urine dip may not have been accurate because of this. Also, I've noticed now my urine has been foamy no matter how much water I drink, so I'm wondering if I should go see my doctor again since I feel discomfort where my kidney is on the right. I'm also suffering from a sinus infection from a cold. Thank you for your help.