Once you've talked to the king, that should be it. Finding the entrance to the well is a bit tricky: I can't remember if it's at the left, right, or top of the well. But make sure it's the correct well, since there are two wells in town. For the well you want, walk left from the king's house and then up, hugging the wall.
I think my game must be bugged if thats the case, tried every angle at the king's well (top doesn't seem to be an option) changed formation of party, redid the pub scene hoping it would reset something, and grinded for like 2 hours to get the mega diaps at the pharmacy and still nothing. Thanks for trying though.