Pain with shallow filling, any suggestions?

I am a dental EFDA. I had an OL #14 filled with composite. Over a month this tooth has ached now off and on. Sensitive to only cold, pain is starting to linger longer , I feel pressure in cheek area where root of the tooth is. No infection seen on X-ray, filling was shallow barely into dentin. I would hate to have an RCT but it feels to me that’s where this is heading just from the symptoms. IDEAS? Replace filling with a base? Or place temp filling? Or just do the RCT? Amalgam perhaps? Help.