Problems after an oil change

1996 dodge ram 1500, 5.2l V8, Automatic trans.
I sent my truck in to a national chain for an oil change. A few days, and a few hundred miles later, I noticed fresh oil on my driveway. I looked under the truck and saw fresh oil all over the bottom of the transmission and frame. I checked the oil level and even with the oil that had leaked, it was still reading at least 1qt over full! I took the truck back to the servicer and they said that my oil pressure switch was leaking and replaced it free of charge, and assured me that they would make sure they spoke to the technician about double checking oil levels. A few days later, my CES light came on with the following codes: 32 Short or open in the EGR solenoid circuit. Check for loose, broken, or shorted wire in the EGR valve wiring and connectors. Possible air fuel ratio imbalance not detected during diagnosis, 37 Open or short in CKT wiring or connectors. Voltage out of range at transmission temperature sensor input. Is this just bad luck, bad timing, or did the shop overfilling my oil cause this problem? In the morning, the truck starts and idles just fine. As it warms up, it starts to idle erraticly. Once it reaches operating temperature, it won't idle at all and stalls if you take your foot off the gas.