structural engineering/mechanics vs solid mechanics

I recommend you register.

I recommend you list what you like about each field & the differences between the 2 as you see them.

Simplistically, solid mechanics mostly deals with how individual objects behave/react to external and internal influences, singly. With similar simplisticness, structural mechanics mostly deals with how multiple objects behave/react to external influences externally and internally, together.

Also, solid mechanics can be more theoretical, in it's nature, while structural mechanics can be of a more practical nature.

First, ask yourself what relevant classes have you had so far, and what did you like, and dislike, about each one?