I always ride with ear-plugs. The key is when you put them in you have to hold them there until they expand in your ear canal. Sometimes you may have to push them in further. They have to have a tight seal. Sometimes if there not right I will pull over take my helmet off and redo them.
As for the seat, try some bike-shorts. I've used them for years and would'nt ride without them. They make any seat more comfortable. Here's a link. Only $30.
http://www.performancebike.com/bikes..._400000_400065