The yellow stones are called Tonsilolith
They form when your tonsils get infected and the holes or crypts are big.
Just the presence of tonsil stones are not anything to worry about.
The only treatment is removal of stones by removing tonsils which is done only if indicated by proper history and examination.
If they are not causing any problems then you can ignore them but if you have any concern meet an ENT specialist.
Next Steps
Meet an ENT Specialist if you have any concern
Health Tips
Do warm water gargling with salt twice daily
Avoid cold and Sour food stuffs