Blood pressure different in both arms?

Hi everyone, I'm new here so please no negative comments!

I took my daughter to the doctor today because of her heart problems. She's been experiencing stabbing pains in her chest and a pulling sensation in her left arm for a while. She has a very limited ability to walk, climb stairs, etc. That was also the reason we went to the doctor.

Today her blood pressure was measured in both arms and it was different.

My left arm was 124/98 and my right arm was 104/81. They measured it three times because the doctors weren't sure. The third time, my left arm was 127/96 and my right arm was 107/68. My pulse was 124, and after sitting for a long time, it was still over 120.

But no one wanted to explain to us what this could mean? I mean, I don't find it convincing that a 14-year-old would have such symptoms and then her blood pressure would be like this.

An ECG and an echocardiogram were also performed, and no one told us the results. In the end, we were referred to the hospital for a long-term ECG without any findings or discussion. I'm certainly worried.

I would be happy to receive an answer!!