Hello !
You have possibly strained your knee ligaments that support your joint or inured your meniscus which provides shock absorption for your knee. A physiotherapist will be able to provide exercises and manual techniques to restore pain and walking. Alternatively visit an orthopaedic for diagnosis and investigations like MRI if needed
Next Steps
Visit a physiotherapist for further treatment to reduce pain and feeling of tightness.
Health Tips
Wear a brace if knee is buckling to protect the structures . Ice if swollen not heat