Hi I Have Been Having Left Sided Chest Pain For

Hi I have been having left sided chest pain for about a week. No shortness of breath and not super painful but noticeable. I have a history of a PE 3 years ago so I went in to the ER tonight. They did a d-diner test and it was elevated. So they then did a CT angio and said all they could see was my old clot still there. Do you think the old clot caused my d-dimer to be elevated or what could have caused it? Thank you.