I think you need to give it a bit more time. When my husband commented on the shrinkage of his lymph nodes about 1-2 weeks into radiation, the RO said that it 'wasn't him' (meaning the radiation), but was probably the cetuximab which started a week prior to radiation. Just as it takes radiation a while to stop at the end of treatment, it takes it a while to get going.

I hope that you will start getting some relief from the referred pain soon. If it goes away and comes back, don't fret too much since as the tumor shrinks, you will have inflammation from the radiation damage.

Glad to hear the nausea is more manageable.
Maria