Master warning light, brake light, check engine light and no codes

So, I've checked the other threads and don't see my exact problem: Yesterday, as I was leaving work, the master warning light, check engine light and brake light (exclamation point in a circle) all went on with a warning chime, so I took it to the nearest mechanic. It sat overnight and when he looked at it this morning, he said there were no codes on it and he couldn't reset the check engine light. The other warning lights weren't on this morning.
Additionally, in the 2 miles to the mechanic the engine seemed to be struggling a bit. The roads are fairly flat, but it seemed as if it were going up a steep incline.

Any hints?

 

Thanks.