What Causes Pain And Stiffness In Knee Joints?

My name is Asha Karande. I am a 68yr old female.I was suffering from urinary tract infection and amoebic collitis 2 months back. I was treated with tablets of ofloxacin 200mg and ornidazole 500mg for 10 days.I got relief from dysentry and UTI. But since then I am getting severe pain and stiffness in both knee joints [more in the left knee]. Is there any relationship between the medicines consumed and the knee joint pain? I had experienced the same pain some time back when I had taken the same medicine though at that time it was for a short duration. There is no swelling in the knee except for some mild tenderness. Movements of flexion-extention in supine are not painful but weight bearing is very painful i.e. walking and climbing stairs. I cannot tolerate Diclofenac and Aceclofenac tablets. Can you advise me some remedy for it?