It's been almost 4 months since i got my first software engineer job.... They only have me doing test support. Should i be concerned? Or is this a regular thing?

Depends on everything really.
I would start looking for better opportunities.

Adults call it, "paying your dues." When you're the ranking FNG, you do the shit work. New architects aren't designing skyscrapers. They're confirming the dimensions of hand-washing facilities in McDonald's bathrooms.

It takes years to get where you want to be.

Pretty normal, as you learn more about their processes you will be able to offer your services in other projects, but for now you gotta put in the grunt work.

Been there. Still there. 6 months into the job. After 3 months of shitty training of stuff we already knew.