Chronic itching near chin/jaw. tiny little bumps. always in the exact same location. could this be eczema ?

Possible: It's very possible that this could be eczema. It could also be a contact dermatitis, fungal infection, drug reaction, or even psoriasis, amongst other possibilities. If it bothers you, I recommend that you have it evaluated by a dermatologist to determine the diagnosis and best treatment options.

Possibly: This syndrome may also be caused by the skin trauma and irritation caused by shaving with electric shavers or razor blades. I would experiment by shaving with one or the other,changing soaps or lotions and see if it makes a difference. Eczema localized to the chin would be unlikely in my opinion. A dermatologist is better qualified to answer your question,however.