What Causes Numbness On The Legs And Hip?

With no pain, my left leg started going numb from my hip down around January this year. It would happen randomly a few times a week, then worked its way up to a few times a day and at times more. Now it isnt only when I m walking/running/getting out of car, it happens when I m in a sitting position now. There have been a few incidences where my leg feels as if it is going to go numb any second and this will last for up to an hour. [similar to feeling like you have to sneeze but you dont] I ve had xrays for my back, I ve done physical therapy and seen a neurologist who did a muscle test [?]. Last week I saw a chiropractor who checked me out & said it doesn t seem like it is anything mechanical and suggested a sonogram thinking maybe it s something going on inside. Says since I m 49 [5 6 124 lbs] maybe there is something female going on. Since, I noticed the other day in my bathing suit that my left side pelvic area is bigger than my right [my lower stomach in pelvic area is lopsided] ~Is that where my ovaries are located? Could peri-menopause be causing this sensation? I m very active and athletic and this sensation though it does not hurt is driving me crazy and starting to worry me.