The words "since" and "ever since" are both used to indicate a starting point in time. However, there is a subtle difference between them.
Since
Indicates the starting point of an action or state that continues up to the present or some point in the past.
"I’ve lived here since 2010."
"He has been waiting since noon."
"I have lived in this city since 2010."
"We have been friends since childhood."
Ever since
It's used to emphasize that something has been happening continuously from a particular point in the past until now. 'Ever since' adds a stronger sense of continuity and duration from the starting point up to the present.
"I have been happy ever since I met you."
"She has been afraid of heights ever since she fell off a tree."
"I’ve been interested in music ever since I was a child."
"She has been successful ever since she started her business."
In summary
"Since" simply marks a starting point, while "ever since" emphasizes that something has continued without interruption from that starting point to the present or another point in time.