No one here can diagnose your problem. We can give you some tips, pointers and suggestions but we are only people with back problems ourselves. There a great many things that could be causing your back and leg pain such as back strain, sciatica, etc. You should go to your physician and he/she can begin the diagnosis process. I hope it is a strain that will resolve on its' own with no lasting issues.
Let us know what you find out. If it is something more & you have additional tests, keep us updated and we can help explain what the different test are and what they show. If you get an MRI report, there are many merabers who can help you decipher some of the medical lingo in it.
Good luck and welcome to the Health BoarRAB.