Suggest Remedy For Pain In Legs On Walking

Hello doctor,
I am 40 Male, Weight 58 Kg from India, About my lifestyle : i work from home. As my work doesn't permit me, so i never walk, almost 16 hours i keep sitting in front of computer for my work, and not even walk half a KM in a day & don't get time also. My problem : when ever i walk all my leg bones pain too much, if in case i step wrong or on uneven surface then i feel so much pain and feel like minor hairline kind of fracture or muscle pain, I am not able to do push-ups just because my arm knees dosen't take my weight, so i avoid it, recently i feel all my bones of hands and foot legs etc.. are so weak now that i feeling very fragile, and i also feeling sinking or height loss. pls. let me know what kind of calcium & D3 vitamin etc.. is good for me to recover from all that, please note that due to my work i unable to walk much or go to exercise etc. in gym, My history : I had Jaundice in past some 9 years back and also TB some 12 years back. Please do the needful and advise be the best medicine. Best regards