Hello sir! myself im a medical student since few yrs im facing several problems like lower limbs weakness, tingling sensation, vertigo while walking feels spongy type , sometime headachenes, i did some test as mri of mine lumbar spine which had shown stenosis but after few months later when i did next mri of lumbar spine then it was normal but my problem was not cure still i feel lower ,upper as well as middle back pain including shoulder also not only that i also did bone scan which was normal.what may be the exact cause and what should i do sir plz help me