Can you have a pulmonary embolism for months? i don't know if it's just a disk problem but awful pain center back/rib/hip area,have siatica to

Pulmonary emboli: You can have chronic PE, usually due to incomplete resolution of prior acute PEs. The symptoms include shortness of breath and chest discomfort. It can lead to pulmonary hypertension. In your case, there are many causes of back pain, so best bet is to see your physician to help sort it out.

Hard to say: typically Pulmonary embolism would cause worsening issues like difficulty breathing, heart palpitations, fever etc. So unlikely it would go on for months, likely days but you go downhill pretty quick if not treated right away since a PE is an emergency.