Hello and hope you are doing well.
Your symptoms could be due to an infection, as urinary tract infection is the commonest cause for pain in the urethra. The other possibilities are trauma and inflammation due to any cause like stone, sexually transmitted diseases, urinary retention, chemical irritation, certain medications and sometimes tumors of the urinary tract. Ruling out each diagnosis starts with a clinical examination and then the battery of tests done are urine analysis, urine culture, blood tests, x ray of the abdomen and an ultra-sonogram. There are other tests like IVP and cystoscopy which may be done if the need arises. To find a cure you need to consult your primary care physician for proper assessment.
Hope this helped and do keep us posted.
sounds to me like need to see a dr! some of the symptoms sound like a uti. saying that though not sure about lower baack pain ie kidneys are somewhat hgiher up around the flank, just below the rib cage at the back. ie not so much lower. When you say bubbles, i have chronic kidney disease and my urnie is quite dark and has the appearance of a head of beer! is this what yu mean as bubbles?? cant comment on the frequency though as to do with kidney disease as i have no bladder but a bag an so it crains constantly. I belive that the output is far less, as is in my case, but not sure about frequency ie if that is a symptom of chronic kidney disease. certainly is one of a uti though so I suggest a trip to the doc asap