Ohh I have read them, and have always found the rules to be extensive and confusing...
What I find the hardest, is to know when to end a sentence or add a comma.
I'm not being a jerk, honest question, wouldn't it be:
I'm not trying to be insulting, but maybe you'd be best off to review the rules for commas. For me, the issue arises when doing dr names/titles, but otherwise, they seem to be straight forward. Who knows, maybe you could become an SS commatrooper and start berating customers who insist on improper comma placement!
Your edit is correct, by the way!
There are no free or paid comma checkers because commas are the most complex and therefore most misused punctuation mark in English. Some usages are simple: a comma after every list item and before the last list item too (if you like Oxford commas, which I do). After lists, most people have a slightly muddier understanding of when exactly they are used. For instance, do you know why your edited commas are correct?
Correct commas usage can be determined 95% of the time by remembering the definition of a sentence. As basic as that sounds, if you know that a sentence is one complete thought with at least one subject and one predicate (simple or complex verb), you can use that knowledge to decide when to use a comma. A very common comma error is called the comma splice. This happens when two sentences are joined by a comma only. This is incorrect. Two independent clauses (another name for a complete sentence) are most commonly joined with a comma and a coordinating conjunction. You can remember them with the acronym FANBOY (for, and, nor, but, or, and yet). You cannot join two sentences like this:
I went to the store but Henry was already there.
Instead, do this:
I went to the store, but Henry was already there.
"I went to the store" and "Henry was already there" are two complete sentences and therefore cannot be combined with a comma only. In this case, I used the coordinating conjunction "but".
You can also use subordinating conjunctions to join sentences (there is no easy acronym for these, unfortunately), but I think fewer people have problems with using subordinating conjunctions because it seems more obvious that a comma should be used. For instance, this is what you did when you corrected "For me the issue arises..." to "For me, the issue arises...". "For" is a subordinating conjunction.
This situation happens when joining an independent clause (a complete sentence) with a dependent clause, which is not a complete sentence and cannot stand alone. "For me" makes no sense by itself, so it has to be joined with a complete thought ("the issue arises when doing dr names/titles") by a comma. Note that the comma is only necessary when the dependent clause comes before the main independent clause; otherwise, you can join it with no other punctuation mark ("The issue arises when doing dr names/titles for me", though this construction is obviously less clear).
Reading about rules can be helpful, but the #1 best way to learn about proper punctuation is, in my opinion, to read books, especially books with a better reputation (I won't get into what that means but instead leave that to you).
P.S. Do you know why I didn't use a comma in my last sentence? "I won't get into what that means but instead leave that to you." Shouldn't there have been a comma before "but"? No, because the two halves of that sentence ("I won't get into what that means" and "instead leave that to you") are in fact not two halves but an one whole sentence. You can tell this because the subject, "I", is the same in both sentences. This is why no software exists to perfectly determine proper comma usage.