Can you please help me with issues with backfiring?

Hello,
I have a 2006 Dodge Charger. I had a tune up done on my car in April. After my tune up my check engine light would come on and off periodically. My mechanic said it was just the computer resetting itself, and that the issue would repair own its own. The issue has not been repaired and it has gotten worse. I took my car back to the mechanic to fix whatever he did wrong and now when I drive it for about five miles, the car jerks, the check engine light comes on, a light that looks like a lighting bolt, and the traction light. One mechanic said the coil packs were the issue because I was getting codes that the car is back firing on 2 & 5. Another mechanic said something more costly. Does anyone have any idea of the issue because this didnt happen until my tune up took place? Please help me.