This is really strange.
Last Saturday I trained back and biceps and also legs.
I did dumbell rowing with one hand while supporting my upper body with the other hand which I placed on a bench. The usual way which you do dumbell rows. But for an unknown reason in both of my arms the ellbows hurt when I used them to support my upper body. I don't know why. Maybe it was the pressure which was on the joint when I stretch out my arm to support the upper body, I don't know.
Later on the same day my right arm suddenly started to hurt when I stretched out my arm. The pain lasted about 5 minutes and then vanished but in the following days the same armpit always used to sting when I used the arm. I went to an orthopaedist and he did an ultrasound of the tendon and it looked normal. But since the stinging still occurs I did not train the arms anymore and also no upper body.
Yesterday I was in the gym and trained legs and also did some cardio and I noticed that during the cardio my armpits feel uncomfortable when I pressed with my arms against the handles of the bicycle. And now my left arm also hurts when I stretch out my arm!
I don't know what this is and when it will finally go away. It's been over 1 week now and it doesn't get better at all. Now it's even stronger on the left side than on the right side. The whole time it was only on the right side and now it's left, too.