biceps injury

hi, I worked out for the first time in about a year a few days ago. of course, I went light and easy, but today (2 days after), both my biceps (I guess more the tendons, around the elbow), are extremely sore, to the point of not being able to extend my arms fully.
It’s gotten worse than yesterday.
I didn’t notice any immediate pain while I was in the process of lifting.
I’m worried that I’ve injured myself, but the fact that its both arms leads me to think its just soreness, but I’d like to be sure.
Thanks!