Hello and welcome to HCM,
Knee pain can occur due to multiple reasons like pain due to
injury / trauma to soft tissues, bony tissue or inflammation in the joint space.
Is there history of trauma or injury to the joint?
Stiffness and soreness is knee joint can occur due to muscle spasm.
Bursa and cysts across the joints can also lead to pain and stiffness.
Pain when sitting for long time and walking for long is suggestive of muscular problem.
I suggest you to consult an orthopedician for clinical assessment of the joint, X-ray to look for the bones and soft tissues around the knee joint.
Muscle related disorders are managed with muscle relaxants, pain killers and
physiotherapy.
Hot fomentation will also help.
In case of inflammation of surrounding tendons or ligaments, anti-inflammatory drugs are also required.
Please consult your orthopedician for clinical assessment, diagnosis and thus management.
Thanks and take care
Dr Shailja Puri