I understand you must be suffering from severe pain. Knee joint is very complex joint made by 3 bones - femur, tibia, fibula and knee cap - patella. Several ligaments, cartilage and menisci are covered all around. So pain in knee joint may be due to several reasons and sometimes it is very severe. It may be due to some internal injury like cartilage etc or may be due to deficiency of calcium, vit d or uric acid. So in general I would advise you to please go for proper investigation so that the reason can be diagnosed. In the mean time to get relief from pain and stiffness please follow the physio measures:
precautions-
1. Avoid prolong standing. Standing on one leg or running for time being if its painful.
2. Take care while bending your knees, it should not directly strain your joint.
3. Avoid heavy weight lifting. 4. Wear shoes with good arch support, do not wear high -healed shoes.
5. Use the correct positions during activities so that you do not strain your muscles.
6. Try to change your sitting position every 15 min so that it should not give strain on your knees.
7. Avoid sitting on floor with both knees bending.
8. Take diet rich in calcium like milk, dairy products, banana etc which will enhance your calcium and gives you strength.
Treatment -
1. Use of cold or hot packs which ever suits you - apply ice or hot pack to the painful area and massage for near about 10 minutes. Make a habit for doing atleast twice a day initially.
2. After this using your thumb massage your knee area gently.
3. Do some knee (quads) isometrics atleast 10-15 times with the hold of 5 -10 seconds. Also you can do some knee strengthening in the mean time.
The above treatment will give pain relief and discomfort. In the meantime please contact any physio who will study your daily routine, symptoms, degree of pain etc and accordingly will give you the best treatment plan.
Good luck and get well soon.