You are new to strength training? Getting back into it? I would think it's just some general stiffness. Shouldn't be a problem. You aren't talking about sharp pain, right?
Yes, I'm new to strength training. I've been doing burpees for a little over a month now but I just intensified my workout routine a little by doing unmodified push-ups paired with burpees and jumping jacks. I'm not really good at describing pain but I THINK its more of a stiff and sore pain than sharp.
I think it's probably fine but maybe someone else will have an idea.
If you are holding in your abs to support your back during the push up(like you should be doing) then you are working that muscle and making it stronger. Cobra pose in yoga might help to stretch that muscle to make it feel better. those round ligaments might be sore and need a good stretching also. Those can be sharper pains that just the muscles