I have pain

Hi to everybody.

I am new to the training. I started this year. When I went to work I was doing 20-25 min training always with warm-up and cool down. For several weeks I started doing 40-50 min training (because of coronavirus I stayed at home so I have more time)

Today when I was doing my workout I feel a pain in my left upper back when I was doing one of the exercises. The pain was like when you doing stretches and you stretched more then you have to. I skipped the last 2 times when I had to do this exercise and ended my workout, But I finished my workout. I have to say, that I am doing a beginner version and I'm trying not to force myself. Even sometimes I had a feeling that I didn't do anything at all, that's how lite my workouts are. :)

The question is: Do I have to worry about it and do I have to continue my workouts this week or do I have to stop until I feel better. Now I don't feel the pain at all. I didn't feel the pain even the rest of my workout, only when I was trying to do the specific exercise.