My right knee pain (behind) Is accurate.

I am Dev here, not sure I am good in expressing here. When I sit in indian toilet position for a min then while getting up I cant place my right foot for a min or so . Slowly post the time I place my foot down. While I place my foot and try to step forward I can sense some imbalance like my head is kinda turning ....which lasts for few seconds not sure my explanation is accurate. I do have lower back ache which is not chronic I am not sure the pain is radiating Though this challenge has occurred off late may be from 15 to 20days I am 45yrs weighing 72kgs I do walk everyday and maintain healthy diet May be I can explain on phone little more better...you valuable suggestions will be of great help to me