I have 2 lymph nodes swollen that my doc said are ok. If it was cancer, how long would it take for them to get bigger? And is it bad both are swollen?

It really varies. There are many causes for swelling of lymph nodes (lymphadenopathy.) the vast majority of time this is due to infection and/or inflammation in the area. If the lymph node swelling is getting larger over a few weeks, it's important to discuss this with your doctor. http://www.mayoclinic.com/health/swollen-lymph-nodes/ds00880.
Depends. If the lymph nodes are cancer they typically will get bigger in less then 30 days, some cancers can seem to grow almost daily. Having two swollen lymph nodes does not mean it is bad. Lymph nodes can swell for many reasons, not just for a cancer. I would make sure you ask your physician, and follow up with your doctor.
Monitoring Centers. Lymphatic system absorbs/carries things too big to go into the arteries/veins like bacteria eaten by white cells and digested food. Lymph nodes "taste" the lymph for anything bad like bacteria/viruses/cancers, etc. When it detects a problem, it alerts the immune system and your body reacts. They enlarge in response to the inflammation they create when they react. They shrink when all is well.