Certified GKH Gardening Expert
What you are seeing is gummosis – it is a gum/sap that oozes in response to injury, whether by insects (such as the peach tree borer), mechanical injury (such as by poor pruning - did you prune your tree recently?), winter damage, or virus/disease.
Below are links that will assist you in diagnosing your tree.
(Cornell Univeristy PDF – cankers on trees): https://bit.ly/1E6AIAN
(Peach Tree Borers) https://www.gardeningknowhow.com/edible/fruits/peach/peach-tree-borer.htm