First things first: how long did you wait? Chia seeds aren't fast friends. They need at least 20-30 minutes to start plumping up. If you checked after five minutes, stop it. You’re not a chia seed whisperer yet.
For the best texture, you need four hours or overnight. Yes, overnight. Let them soak in their own dreamy, gel-filled destiny. Rushing a chia seed is like rushing a good nap. It just doesn’t work.
If you did wait overnight and it’s still runny? We have suspects to question.