I was diagnosed with a kidney stone a week ago when having left lower abdominal pain and back pain . it appeared from x-ray to be in my urethra perhaps . now i'm having pain in right sides . can it travel to another side ?

No travel upstream: Kidney or ureteral stones can be in the left kidney or ureter, the right, or both sides. There's no physical way for a stone to travel from one side to the other side, because that would mean a stone would have to travel down into the bladder and then back upstream the other side (not possible to do). A stone in the urethra can block the bladder, backing urine up both ureters and both kidneys.