Telling us the Check Engine light is on without telling us what code is triggering it is a waste of time.
And assuming it has something to do with the work recently done - well, it is reasonable to assume that, but again, without the code or codes being stored - there is nothing to discuss.

The Torque app is one way, I like my ultragauge:
UltraGauge OBDII Scan tool & Information Center

$61, less than I paid for it two years ago.

Of course, you can go to many Auto Parts stores and they will read the code for you, and we can go from there. But I highly recommend you get SOMETHING to read the codes yourself. If you can figure out how to set up your smart phone, you can figure out how to get one of these apps working or get the Ultragauge configured. And we are all here to help if you need help.