Marie Davis,
The pain, redness, swelling certainly sound like plugged ducts, not yet
mastitis but certainly could progress to this.
The "milk clots" that are large and slimy (oily?) and evenly distrubuted
throughout the milk and dissolve when you rotate the bottle - could this be
fat globules?  Like oil mixed with water?  Why this is only on the one side
now I don't know.  Let us know the outcome.
Laurie Wheeler, Rnc, Mn, Ibclc
Violet Louisiana