Knee pain is very common....specially in post menopausal and overweight women
As you tested negative for thyroid levels its a good news.... however knee pain is a collective term ranging anywhere from osteoarthritis to patellar problems... lack of exercise,calcium deficiency and body weight also contribute a lot to knee pain.
With the information you provided i would suggest you start ..... Non weight bearing Knee exercises,
Static exercises for knee is a great way to achieve hamstring and quadracep muscle strength without stressing the knee much.... any non weight bearing closed chain exercises like a static bicycle or a cross trainer will do a world of good.
To relieve knee pain you can have sessions of IFT vector 90 along with the exercises
And yes have a patellar knee cap.
I have treated more than 100 knee pain patients in UK and India with 90% relief of symptoms through above mentioned prescription.
Do resort back to me with any furthur querries.
I totally agree with the suggested static exercises and IFT. Besides, you should also start applying joint protection techniques like not standing or sitting for too long. Take breaks in long continuing activities. Use a small step unilaterally to relieve weight off from the knee if you have to do some task in long standing. Joint protection techniques along with regular exercise will keep your knee joints in good condition.