Hi I Have Been On Sick Leave From Work Since

Hi I have been on sick leave from work since October 2015 due to a lower lumbar back complaint .I have not been sent for an Xray,mri or CT scan and am no closer to finding out what caused the problem, nor am I fully better ,but for financial reasons am having to return to work as a specialist residential dementia carer .I am 34 years old and am still in constant pain ,i cannot sit,stand or walk for too long otherwise my spasms in my left leg start and I get a pain in my left hip and groin .Please help as I need to go back to my GP armed with information that may get me checked out fully.