I have knee problems. Why do you think my foot and ankle hurt?

See below. Due to the knee problems your foot and ankle are bearing more of the weight and compensating in position there fore they have more strain placed on them.
I would look . To see if you have a flatfoot or one that "hyperpronates". This would throw the biomechanics off and put strain on the ankles and inn knee as well as possibly the lower back.

Related Questions

My knees and ankle hurt when its cold, is this normal?

No. It's arthritis. It's arthritis. Get some blood work done. And stay warm. Read more...
Yes . People commonly complain of achy joints when the weather is cold. If its mild and goes away quickly with activity then it is probably nothing to worry about. However, at your young age, if its more severe or getting worse then talk to your internist or possibly a rheumatologist. Read more...

Knee and ankle hurt so much she cannot walk, when she does try to walk she gets nausea and shaky?

Be seen. Probably the best option is to be seen and thoroughly evaluated. Once an accurate diagnosis is made, appropriate treatment options can be discussed. Read more...