is this a uti?

I'm having burning when I pee sometimes.. depends if I drink loads of water or not..
(Been having this for a week)
No cramps...
But now I'm having pains in my upper belly not like cramps more like someone is squeezing my insides! 
Can someone help me! 
The pain is  on and off 
Also having some back pain....
( but last night i had pain due to wind)