I am seriously concerned after reading many horror stories involving root canals and infections, but I'm hoping I can get some advice.

Here is my issue: I had a root canal and crown done by my regular dentist 3 years ago. I haven't had any issues with it at all until recently. I started having some pain in what I thought was the tooth next to my crown, which has a big filling in it. After just a couple days of pain I went to the dentist. (I didn't go to a dentist from the time I was 10 years old to 25 years old, and at that time with good insurance I had all my teeth fixed which entailed pretty much all of my molars getting fillings. Ever since then (about 10 years later) I don't put off going to the dentist and have regular checkups and cleanings. Anyway, so my dentist takes an X-ray and tests my teeth to see where it's hurting, and he said the X-ray looked fine, and I was having more sensitivity on the crown than the tooth next to it. I thought that couldn't be because I distinctly remember my dentist saying, "well this tooth will never hurt again." So, my dentist refers me to an endodontist to check the root canal and crown, and prescribes me Vicodin. At the time I thought maybe the pain had even gone away because I had taken Tylenol earlier, and was in no pain. I didn't pick up the prescription for the Vicodin because I didn't think I'd need it. Well over the weekend I felt more pain, and made the appt and saw the specialist on That Monday (saw regular dentist on Friday). The endodontist took an X-ray and tested sensitivity. I had developed pain in my jaw all the way to my ear by then, and my gland on that side was starting to hurt. He told be I had an infection under the root canal and prescribed me Amoxicillin and told me to take Advil. He said if this didn't fix the problem he would perform a minor surgery where he cuts in through the side under the root canal and removes the infection (an Apicetomy). I have now been on the Amoxicillin for 5 and a half days, the pain goes away at times, but others its excruciating making my ear and gland and jawbone hurt. I've taken Motrin and Vicodin a lot this week. I'm fearing the antibiotic hasn't helped. I am going to call on Monday to make another appt with the endodontist, but after reading a lot online I'm worried an Apicetomy isn't the best option. I am scared of the infection getting worse. Advice please.