HELP! Poor signal & resets when I put it in my pants

[elco]

I wonder if you good people could help. :)

My XDA2 is running WM2003SE (The great "XdA2JoJo.v3.2zS." Thanks, pare! :) ) and Radio 1.18. It's been OK for the last 7 or 8 months. I usually carry it in its original leather case in my pants pocket (front left hand side).

Then suddenly cellular signal gets very weak in places where it used to be strong. Sometimes I can make a call only after resetting the phone. But many times this doesn't work. Anyway after going outdoors, signal comes back. :(

After this I put it in my pants pocket. When I pulled it out, the phone was dead. Only a hard reset would turn it back on again. :(

This is repeatable. If I put my phone in my pants pocket, after moving around and sitting down and standing up, the phone will need a hard reset to get going again. :(

I'm almost certain something is loose inside, which could be causing low signal reception and the need for hard resets.

What could be loose?

I'm handy with a screwdriver and have taken apart other phones before. Could I tighten it or fix it myself?

Thanks in advance for your replies! :)