<s>[INST] I am 24 male with 173 cm height and 71 kg weight. I work as a software engineer which involves lot of sitting job. Also from past 2 month i have started going to gym. From past 3-4days  i am feeling strain in my back,its like it is very stiff. Whenever i Sit down or bend i feel a kind of strain in my back ,however it is not pain, is this strain or stiffness only called as a back pain or is it different from back pain? And what can be the reason for it as i am just 24 and i am physically active as i am going for aerobics for last 7 months. One more thing just to inform,i have lost 16 kg in last 7 months with aerobics,can that lead to this strain? I have heard that if once this back pain comes it is lifelong. Is it true or can it be recovered fully? and what precaution should i take.? Thanks for your answer in advance. [/INST] Hello,I had gone through the case and found that it might be cervical spondylitis and Vitamin D3 deficiency which causes pain and stiffness.Go for cervical x- ray and Vitamin D3 test.Avoid long time sitting and computer work. Avoid pillow. Do hand and neck exercise.Take Vitamin D3 once a week for 3 months.Hope my answer will be effective for you.Thanks </s>