Change of Venu

[Mom in Pa]

I lived in Ca with husband had 2 boys. Then divorved got custody of 2 boys and support order and moved to Pa. Since all papers were filied in San Diego they have jurisdiction. Is there anyway to change the jurisdiction to Pa? Also Ex got the boys for visitation over this summer, refused to return them and filied an Ex-parte for custody. I was given a days notice of this hearing. Luckly a friend let me borrow the money and I flew back to Ca. In Ca I needed the local police to retrieve my boys. The Ex-parte was denied, since I retrieved them from the visit. In the papers it states HE is responsable for all transportation. Now the custody is still being sought for from him. The boys have lived in PA for 3 years. And the San Diego courts know that PA is their legal residence. Ex put my oldest in school with no record transfer from his school he was enrolled in Pa. Pa shows those days my oldest missed as being unlawful thus I can be fined. But EX had the boys. Will fine convert to EX? Also Ex has blocked me from any medical records.
In the 3 yrs we have lived in Pa, Ex has only seen the boys a total of 2 months. And 30 days of that, I brought the boys to HIM.
When I brought the boys to him, he would hound me to stay in Ca. I asked for Ex to come to PA to visit the boys, he said no there was no reason for him to come to PA, thus me bringing the boys to him.
My question, with all he has done can he get custody? Also with him violating the visitation order, not returning them and me paying and flying to get them can the court order him to pay me back that money?