2014 Mazda CX-9- Blinking check engine light after service

I recently had a new battery installed on Monday, not from dealer. Check engine light came on the night. Took it in for service Tuesday where I had an oil change and a fuel injection flush. I couldn’t leave my car to diagnoise light because they didnt have any loaner cars and I had to work. Ran great after service. Later that night, after I got off work, my car had a shake after starting. Went away after a couple minutes and drove home fine. This morning, taking the kids to school, shakes for a few minutes and went away. Don’t use my car until later this evening to go pick up kid from practice, shakes the whole way. No shake when I coast and stopped. Stuttered while accelerating then ok. On way home, my check engine light starts blinking. Trying to get appointment first thing in morning. Is it possible something happened during service? My husband told me to ask here first before I start googeling.