3 lumps in my neck I think they are my submandibular immune lymph node glands, they are soo tiny and moveable don't hurt and I am able to eat?

Need to see Doc. Lumps in neck could be enlarged lymph nodes due to infections in the mouth, however, other conditions like chronic infections, tuberculosis, cancer, lymphoma needs to be excluded. Need further evaluation even an ENT consult to make sure that there is no pathology in the mouth, tongue and neck area.
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.