iPhone 6: Service Issues

I bought an iPhone 6 a couple weeks ago knowing what I was gonna get myself into. It had a muffled speaker and earpiece, a damaged housing (slightly bent), and a service issue. I bought all the parts needed to fix the iPhone and took apart my phone and fixed it. The one thing that is needing to be constantly fixed is the service issue.

I first bought a new antenna shown here. I replaced that "fixed" the antenna issue. The second thing I thought was a problem was the dock connector, so I bought another dock connector. Again, it "fixed" the issue. And so again, I knew the housing might of been the issue cause it was bent at the bottom. So I bought another housing.

The whole time, when replacing these parts, I've had it go from Searching constantly to No Service. Before I replaced the housing, I've had to bend the case back and forth and smack my phone to fix it. Along with resetting network settings and restarting the phone multiple times. This normally took 5-10 minutes.

After replacing the housing, every time I stopped using my phone or switched to wifi for a long time, the service doesn't cut out, but it goes to 1x or nothing. After thinking a restart would do something, it would go to Searching constantly after restarting. After taking out the SIM and putting it back in, it goes to searching to no service. The only thing that really helps is if I turn off my iPhone, open it up and take out the SIM. The only times that I get service back is if I'm using wifi for a couple minutes or I switch airplane mode on and off, that's when I get service back but again, it only goes back to 1x.

Is there anything I could do to test to see what could possibly be wrong or something? I really hate bring a tool kit for my phone everywhere I go. It'd be really appreciate it if I got an answer.