Which parts chain = best 2C re throwing codes?...Or is dlr w/Techstream needed?

[nookandcrannycar]

The 'fender bender' re my '07 occurred on October 7th, 2014. I left for NY & NJ on November 14th, 2014. During that period, I started my '07 periodically and backed it out of the garage and into the driveway. One time I drove it, IIRC, 15 miles. No indications (after warm-up) that there were any issues (other than the fender, and being able to open the driver side door ) that needed attention.

I returned to Texas on December 7th, 2014. On December 9th (at night) I started my '07, and the check engine light came on. I waited to see if the check engine light went off after the green 'cool' light went off (after warm-up). It didn't.

Last night I started the car again (again, it started up very quickly). Same scenario as December 9th....check engine light stayed on after the green 'cool' light was no longer illuminated. I drove the car a bit down the street and back (under a mile). Appears to be running smoothly.

Prior to this, the only time the CEL has ever illuminated was on I-20 last summer, north of Tyler, TX. It turned out that I was 2 1/2 quarts low on oil. I added 2 quarts of oil right away. The light didn't illuminate again until December 9th.

I checked the oil level this morning. It is fine.

I often see suggestions on threads to 'take it to a car parts place and have them check for codes'. Would this be the next step in this situation? If so, is one of the major chains (Advance, Auto Zone, NAPA, O'Reilly, Pep Boys, Car Quest) better than another (re accommodating a code check, which tool they use, etc.) ?.....If this is not the correct next step, would the correct next step be a look with Techstream (at a dealership) ?