Not everyone bulks up when they get stronger (like me, for instance). Roughly speaking, 25% of people are endurance types (don't bulk up), 25% are sprinters (bulk up), and 50% are mixed. If you still have a "narrow frame" after a year of working out, you're probably not in the sprinter category.
Benching is fun. I got up to a 365 max at one point, but I was also a powerlifter. Squatting and deadlifting believe it or not can improve your bench. Close grip bench for the triceps also helps significantly. Close grip alone made my bench shoot up around 30 lbs within a month-month and a half. Well, my powerlifting days are over due to feeling like utter crap all the time. So I decided to move on to fighting.
probably should mention that I still compete in running distances 1 mile to 10k(6.1miles)