Your 36-year-old wife has three neck nodes, which have become larger thrice in the past seven months. These episodes of enlargement are associated with pain. The significant point is that they do become smaller with some medicines (antibiotics) given by your doctors. Such enlargement is usually due to infection by bacteria. One of the bacteria is the tuberculosis bacterium. Hence, the correct way to proceed is to look for any infection in the throat. Because you had already seen an ENT specialist, he would have excluded this possibility.
The next step will be to see a chest specialist to find out whether there is any TB in the chest and in the neck nodes. Whatever it is, it needs to be investigated. Occasionally, the lymph nodes themselves may become larger due to other reasons. Hence, a definitive step will be to give some more antibiotics, take a test called fine needle aspiration cytology (FNAC). This is a simple test, which can be done as an office visit to a pathologist, in minutes. If a diagnosis is still not reachable, we can remove one of the nodes and test the same.
Such investigations do take some time. You need not despair because of the delay. For every such illness, very good treatment methods are now available.