I didn't read all of the other responses, but I did read Katie S. (2 below), and I agree with much of what she says about routine. Not necessarily schedule, but definitely routine and getting him to sleep BEFORE he gets overtired :)
I'm so sorry people have told you that you spoiled him. There's no such thing as spoiling a baby! Most babies need to be either nursed or rocked to sleep for many, many months, and that's completely normal (and natural for many moms). My daughter is 19mo, and she is nursed to sleep for her nap, then nursed before bed. (lately, she's been asking to go to bed and falling asleep on her own)
My only advice to help him with the crying before sleeping is to pick him up, rock him and hold him. It seems he needs contact with his mama :) Hearing about the hours of crying and the time of day it occurred definitely sounds like colic, but most babies outgrow that around 3mo when they start to become more self-aware and systems in the body are more mature (like digestive, breathing, etc). Based on this, I agree with him being overtired.
Sleep is one thing we cannot force on our babies (same with eating and pooping), and the quicker I learned and accepted that one, the more peaceful a parent I became. My son rarely slept more than 2 hours at a time until he was 19mo, and I was exhausted and frustrated, but I knew that it couldn't go on forever. I found myself cringing when he would wake up a mere 30 minutes after going down for a nap; I hardly ever got anything done around the house! However, my daughter has a completely different personality and has been a super sleeper since birth :)
It was a life-changing, eye-opening experience to have 2 kids that drastically different from each other. It made me finally understand that there was probably nothing different I could've done with my son, and it more than likely was never my fault that he wasn't a good sleeper. I always thought that if I did this or that or maybe that....
Try to help him to sleep, help him learn and understand that sleep is a good thing, not something to be afraid of. Start the process during the day because generally, the better they nap, the better they sleep at night. How do you feel about bed-sharing? Napping in the car (if he enjoys his seat and being in the car) was a life-saver for me on many occasions.
Hopefully, something in this rambling post will help :)