HI THANKS FOR POSTING YOUR HEALTH QUERY. GOING BY YOUR CLINICAL HISTORY,IT SEEMS OBVIOUS THAT YOU HAVE RENAL STONES AS THE MOST LIKELY CAUSE OF YOUR SYMPTOMS.KIDNEY STONES CAN PRESENT WITH SYMPTOMS LIKE DIFFICULT URINATION,PAIN DURING URINATION,LOWER BACKACHE,PAIN RADIATION TO GROIN,SYSTEMIC UPSET OF FEVER ,NAUSEA AND VOMITING.ONCE YOUR PREG TEST IS NEGATIVE THERE IS NO POSSIBILITY OF YOU BEING PREGNANT BY ANY MEANS.ALSO MENSTRUAL ABNORMALITIES ARE RULED OUT BY YOUR DATES.ALL YOU NEED TO GET NOW IS A PLAIN NON CONTRAST CT(COMPACT TOMOGRAPHY) SCAN OF THE ABDOMEN.THIS CAN DETECT THE TYPE,LOCATION,AND SIZE OF STONE. STAGHORN CALCULI AT RENALPELVIS COULD CAUSE SUCH SYMPTOMS.TREATMENT WOULD INCLUDE-ESWL-EXTRACORPOREAL SHOCKWAVE LITHOTRIPSY.SURGERY INCLUDES-PCNL- PERCUTANEOUS NEPHROLITHOTOMY .IT HAS GOOD OUTCOMES.MEANWHILE YOUR SYMPTOMS CAN BE MANAGED BY ANALGESICS LIKE TRAMADOL.CONSULT YOUR UROLOGIST FOR EXPERT MANAGEMENT. THANK YOU. TAKE CARE