Random Nginx 502, 504, 522 etc - php

Question

At random intervals my site will become unresponsive and the only way to make it load is to do this is the console. Of course this is an easy task but I can't be constantly monitoring my site.
service php5-fpm restart
I don't know how to fix this, but here's my configuration files.
/etc/nginx/sites-available/default
server {
listen 80;
listen 443 ssl;
default_type text/html;
server_name epicmc.us;
root /usr/share/nginx/html;
index index.php index.html index.htm;
error_page 404 /404.php;
# pass the PHP scripts to FastCGI server listening on the php-fpm socket
location ~ \.php$ {
try_files $uri =404;
fastcgi_pass unix:/var/run/php5-fpm.sock;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
include fastcgi_params;
}
}
/etc/nginx/nginx.conf
user www-data;
worker_processes 4;
pid /run/nginx.pid;
events {
worker_connections 768;
# multi_accept on;
}
http {
##
# Basic Settings
##
client_max_body_size 8M;
sendfile on;
tcp_nopush on;
tcp_nodelay on;
keepalive_timeout 65;
types_hash_max_size 8000;
# server_tokens off;
# server_names_hash_bucket_size 64;
# server_name_in_redirect off;
include /etc/nginx/mime.types;
default_type application/octet-stream;
##
# Logging Settings
##
access_log /var/log/nginx/access.log;
error_log /var/log/nginx/error.log;
##
# Gzip Settings
##
gzip on;
gzip_disable "msie6";
# gzip_vary on;
# gzip_proxied any;
# gzip_comp_level 6;
# gzip_buffers 16 8k;
# gzip_http_version 1.1;
# gzip_types text/plain text/css application/json application/x-javascript text/xml application/xml application/xml+rss text/javascript;
##
# nginx-naxsi config
##
# Uncomment it if you installed nginx-naxsi
##
#include /etc/nginx/naxsi_core.rules;
##
# nginx-passenger config
##
# Uncomment it if you installed nginx-passenger
##
#passenger_root /usr;
#passenger_ruby /usr/bin/ruby;
##
# Virtual Host Configs
##
include /etc/nginx/conf.d/*.conf;
include /etc/nginx/sites-enabled/*;
}
#mail {
# # See sample authentication script at:
# # http://wiki.nginx.org/ImapAuthenticateWithApachePhpScript
#
# # auth_http localhost/auth.php;
# # pop3_capabilities "TOP" "USER";
# # imap_capabilities "IMAP4rev1" "UIDPLUS";
#
# server {
# listen localhost:110;
# protocol pop3;
# proxy on;
# }
#
# server {
# listen localhost:143;
# protocol imap;
# proxy on;
# }
#}
/etc/php5/fpm/php.ini
This is hosted remotely because it's too large to host. http://pastebin.pw/683h6n
Here is my Nginx error log - It was too big to paste in here (or anywhere) without crashing my whole browser. The .log is available for download here though: http://uploads.pw/v/480801/