Anybody experience kidney stones after treatment???

So, my husband has had lower abdominal pain on and off for the past two days.  It got so bad this morning that he went to ER.  Long story short...CT Scan showed a 4mm kidney stone!  He has never had kidney stones before so I am wondering if this could be related to the Erbitux?  Or radiation?  Or maybe the fact that he is sort of switching from a liquid diet back to solid foods?  

For those that don't know...hubs was treated with 8 rounds of Erbitux and 35 radiations for HPV+ BOT SCC. Stage IVa. No Peg.  He is almost at 8 weeks post treatment and generally doing well until these pains came along.  Doc claims this stone should "pass" (OUCH) soon and he'll be good as new.  

Anyone else experience this??