I am pretty sure I have a plugged duct. I haven't ever had one, but this afternoon it started aching a little when M would nurse on my right side. Then I was feeling around to check and I can feel a small lump at the top of my areola (like where the areola meets the rest of my boob). Does this sound like a plugged duct?

The lump is small so I am hoping I caught it early. I just nursed M to sleep on that side and I am now planning to take a hot shower and massage the lump then pump afterwards. How will I know if I got it? Does milk come squirting out? Or will I notice the lump and pain are gone? I really don't want this to turn into mastitis!