You've probably hit a soft cap, at which point things no longer naturally drop above your current level. You need to do milestones (flash points, call to arms, nightfall, heroic strikes) as well as participate in raid activities or get clan engrams to progress. If you raid for a couple of weeks, it's supposed to be fairly easy to be near the max. If not, getting above the soft cap happens very slowly, and not at all without milestones. Not word on if bounties can drop above soft cap or not. Might be worth a try.