This sounds like your outer speaker may be broken; this may have been from trying to play music that the speaker physically couldn't handle, or even dropping it wrong. Either way, it's a fairly easy replacement and your speaker should be good as new afterwards. If that doesn't work, try our troubleshooting page for more solutions.
Well there could be a few issues. Given that it only happens here and again, it could be an issue with the camera starting to fail. You can try replacing it, which isn't too difficult. If that doesn't work, try our troubleshooting page for more solutions.
Well, your phone not turning on could be for a myriad of reasons. If you take a moment to look at the troubleshooting guide you can find the ways that it could be broken. The most common issue is usually a battery issue, so i'd start there. Wish you well, good luck!