This may not be exactly what you had hoped to hear, but it is good solid advice and works; you only, have to believe it and take authority in it.
The advice I am giving you comes from a Dr.'s point of view and actually in regards to another age group, but with similarities of "taking control".
First ask yourself what has been "significantly" different in breast feeding this child versus your previous. Discern when the fits began. What stems the need for nursing instead of pacifiers, etc.? If you have asked yourself these things already, and clearly have no good answer, then ask yourself why you are willing to give in and suffer the pain in breast feeding to accomodate what is clearly taking "advantage" of the situation. I know it must hurt terribly with the teeth, so do not put yourself through that.
Your child knows you love him. No matter what is going on, if you have checked all of the reasons, possible, for the necessant crying and fits, and to no avail, nothing will appease him, let your Dr. check for underlying problems, that you cannot determine. He should be more than willing to help. However, if by simply breast feeding, the crying comes to a halt, every time, this is a RED FLAG. You must stop giving in.
Have you tried replacing the "need" by diverting his attention, such as, reading a book to him (to calm and soothe him), or turn on a funny cartoon ( to change the mood), or playfully tickling or wrestling (to get over the anxiety, which last about 6 seconds, truly)? Hey when it comes to our child, we want to do everything we can; we just don't want to create problems for them when they get older.
Here is the fulfilling of the wonderful advice. You may not enjoy (or tolerate) much of the crying, but it will behoove you to know, that in order to overcome, you must endure. After doing all you can, make sure every avenue is covered, by leaving "many" pacifiers, or teething objects, cloths and such in the area with him, and close the door! Put on an ear piece if you have to, but do no give in. The GOOD NEWS is that he will not go hungry, because when he "needs" the food, he will take a bottle. He is too young to think that he has a choice when it comes to "necessity".
This is what I have been told about my own with complications of eating, in general. She was 5, and trying in the same manner to eat what she wanted and refusing the other. It was not healthy, nor wise. The same is true for you.
Best wishes and I pray you will take this message to heart and know, I do not judge, I am a mere mortal mother who has been there and knows that you are special too!