Q:

Does a singular noun after the word "between" need an article? 

Does a singular noun after the word "between" need an article?  
For example in the following interrogative sentence: 

What is the difference between a word to sentence? 

I am not sure if I need to put here an article (where I emphasized) 

A:

To begin with, we do not use to in this construction, but and: 

What is the difference between A and B? 

Beyond that, what article (or other determiner) you use with A and B depends on the discourse context; the use of difference between is irrelevant: 

A and B may take determiners of the same category or different categories. 
If A (or B) has been specifically identified in the discourse, or is familiar to your hearers, you use the or some other definite determiner; if it has not been identified, or if no specific entity is intended, use a or some other indefinite determiner.  

What is the difference between a job and a profession? ...  Both job and profession designate any member, not a specific member, of that category. 
What is the difference between the job we have just described and a profession? ...  Job designates an identified specific entity, profession designates any member of that category. 
What is the difference between the pronoun in example A and the pronoun in example B? ... * Both pronouns are identified specific entities. 
What is the difference between the job John holds and the job of his CEO? ...  Both jobs are identified specific entities. 

There are of course many other rules—for instance, proper nouns are inherently determinate and take no article—but they're all the same rules that apply in any other situation.