Hi,
I was 290 when I started riding, I now weigh 260.My opinion is that you should be aiming for a healthy way of life; and bicycling is perfect for that. If you want to keep at it,
you have some choices. Most bikes come with crap saddles. Try a WTB Speed V, not the big comfort one. It takes a week or two to get used to a new saddle, so give it time. Saturday I rode on mine about 32 miles.The next thing is that lycra is the way to go. Get a
tube of skin lotion from a drugstore (lotion without alcohol in it) and use it before you go out riding. Lastly, Performance makes a nice 3X cycling shirt, and it doesn't cost an arm and a leg.
http://www.performancebike.com/shop/....cfm?SKU=16342

this is the short I use

http://www.performancebike.com/shop/....cfm?SKU=14591