Kidney pain

had this for quite some time, over 6 months i'd say. Ache every now and again in my left hand side/back (between arse & mid back) where (I would presume) my kidney is - the pain is like as if someone is pushing their knuckles in or like a stitch what you get after running (its the only way i can describe it)

Dunno whether its connected but when i go have a pee , I dont feel like emptied bladder, will wash hands and have to have another pee (and pee does come out so its not in my head!) - plus sometimes when i need a pee I get dizzy and flu'ey feeling until I pee and sometimes mainly in evening I pee and about 5 mins later need another pee and could keep doing that for the next hour or so - pee is clear in colour.

Heres the score though - Had a renal ultrasound for both kidneys and bladder at sligo general a week before Christmas and got the results last week from Doctors receptionist and she said it came back clear with no problems what gives? - or what else could i be looking at? .. am pretty sure its not all in my head!

Have got high blood pressure (which I am taking tablets for - but had this kidney pain and urine urgency long before being given BP tablets) and at last blood test Creatinin flagged up red but only just over - am 50 years old 13 stone.