Why iM not getting power to my fuel pump

At first my fuel pump went out and I changed it, but when I started it up it just bucked and made his loud whistling noise then, after trying to figure out what was making the noise, then the fuel pump burns out then I change it again, then after installing this fuel pump it wouldnt come on, so then I would wiggle the connector and it would come on, so then the next day I changed the connector, then it worked again for awhile then it a stopped working again so then I checked all my fuses and relays for the fuel pump and thy were all fine, but I shooke the fuse box and the fuel pump would come on. Then after doing that I checked all wires and they were all fine. So then I took it to a shop and the toldme that it was either the pcm or the bcm and then I went to go pick it up from then the fuel pump would come on at all I did what I would usually do if it owuld quit but it didnt work.