Hi Gina,
There are several possibilities. I don't grow Phals, so I can't tell you exactly what the symptoms of viruses are like on them, but you can take precautions just in case.
If you suspect a plant of being infected, isolate it from your other orchids. Don't let water from it drip onto your other plants and wash your hands after handling it.
Always sterilise your tools (scissors, etc.) between plants - you can dip them in isopropyl alcohol and flame them with a small butane torch (i.e. one used for creme brulee) or larger ones from Bunnings. Alternatively, you can get trisodium phosphate (TSP), available from Bunnings as Tricleanium, and soak the tools in a saturated solution for 15-20 minutes (saturated meaning no more of the powder dissolves).
To me, the last photo looks like mechanical damage on the leaf. Some of the other yellow spots do not, though. I'd be checking for pests (i.e. mites, aphids, etc.) as well as discussing the culture of the plant with other growers on this forum.
