tingling/numbness in my right arm into my hand and fingers and my right leg below my knee into my foot and toes. not all the x

i have recently been diagnosed with arthritis of the right SI joint, my physiatrist believes there is another issue, but tests have not shown anything besides the arthritis.  i have no other medical issues except migrains which i take topamax (50ml 2x daily) for and have been doing so for about 2 years.  i am 37 5'3" 125lb i am married and have two children-10 & 8years 

i had basic blood work in dec of 2009 all of which was normal