Suggest Treatment For Lower Back Pain And Headaches While Bending Down

I m on synthroid 125 and am having some lower back pain. I ve never had a problem with my medicine for the 1 year and 1/2 I ve been on it. I felt sick the past couple of days but not flu like symptoms - no fever, not throwing up. More Lower back pain, headache but only if I bend down, really tired and weak. I never called the doctor bc it happens over the weekend and am feeling better today.. Much better but the back stuff lingering and not full energy.