Do people with subconjunctival hemorrhage have a lot of pain?

Usually not: Subconjunctival hemorrhage is usually not painful at all. Some people experience an initial sharp pain that lasts for a few seconds, but aside from that, it should be painless. Persistent pain needs to be evaluated.

No pain: This is a spontaneous condition that always resolves in time (few days to weeks). It becomes more common with age, use of blood thinners including Aspirin and nsaids, straining (valsalva). It may or may not be associated with mild irritation, but pain is not associated with it. If you're having pain, you should see if it is something else.