I purchased a Norwegian pine shed some years ago and after painting with a water based paint the knots seeped through in significant sized globules which are sticky and problematic to remove.Is there a “solvent” available to overcome this problem?
You needed to seal the knots prior to painting. No matter what you do, it will continue to bleed through.
Remove the paint around the knots. Use solvent such as turpentine to remove the sap with a scraper and rags. Seal the knots with an appropriate knot sealer (available at any paint store). Prime the sealed knots, perhaps twice. Repaint the whole surface to even out the coverage.
Sometimes water based primer-sealers are acceptable as "knot sealer"; ask at the paint store or read the label. If this is the case, then the sealing and priming would be the same step.