column information moves to the next column
 

I maintain a database that has 5,000 lines. I've noticed that information
contained in a several columns has shifted to the next column and all
alignment is gone.
example, telephone number- area code in one column cell, telephone number in
one column cell, I put it in correctly and then at a later time I notice the
information shifted to the right and no area code and telephone number in
area code section.
I do have to sort at time, could this cause the problem because it's large.
Is there anyway to protect the information from moving. Tell you now, I know
nothing about macros. Any help will be greatly appreciated