Hi i am Dr Ahmed Aly  
  thanks for using healthcaremagic site ,
I had gone through your question and understand your concerns ..
    Actually it may show this kind of muscular spasms if you have multiple 
spinal disc herniation in addition to abnormal calcium levels that may cause tetani in all your muscles all over your body and it is diagnosed by bilateral 
leg cramps or tremors if reached peak levels .for your 
low back pain i thinh that is a sort of sciatica both are of neurovascular origin of your spine .
   For my patient i suggest some lab investigations like calcium  , 
magnesium and potassium levels to exclude hyper or 
hypocalcemia and Xrays , MRI , CT on spine to diagnose the  site of 
vertebral herniation for proper management .. for now i consider NSAIDS painkillers like advil , hot massages with topical gels , muscle relaxants , B12 multivitamins , 
physiotherapy and even yoga are effective in such cases till the results of your tests are done . 
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Any further clarifications feel free to ask.