Most general physios can also ultrasound blocked ducts - the equipment is the same as the ultrasound that they use for muscles. Make sure when you make the appointment that they are happy to do it though.
Have a think about things like seatbelts, bras, slings, baby knees when they are in slings, and anything else that might be pushing on the affected area and making things worse. Also - go gently on the massage. Too vigorous and you can cause a blockage rather than clear it.
And heat before feeds and cold afterwards is also helpful.
To clear the blockages you have to get the breast really, really empty. This usually means feeding baby, pumping, and then hand squirting out the last little bit (and hopefully the blockage). Give hand expressing in the shower after a feed a shot - that was what usually worked for me.