Morning Snowflake!
You would be amazed how high the % of people over 55 with undiagnosed / undiagnosable BPPV is, I would get this looked into again. Even if the "test" (called Dix-Hallpike) is not positive it may be useful to learn the treatment maneuvers and try them for a few weeks.
Dizziness can also be attributed to Cervicothoracic conditions (your neck and upper back), which is why the massage may have helped. Get someone to look at your Scalenes, Sternocleidomastoid, and suboccipital muscle groups. Dysfunction in your neck can lead to many symptoms including dizziness. Have you also talked to your doctor about any medications you are currently on, discuss the side affects, this can be easily overlooked.
As Andy said occasionally blood supply to the head can be impacted, especially during certain positions of your head. Do you get dizzy turning your head to the side for 30-40 seconds? (if so stop this test straight away!).
How about your eyes? How is your vision? If the input from your eyes is poor sometimes if it doesn't match the input coming from your inner ear it can cause vertigo / dizziness.
Dizziness can be quite a complicated topic! Make sure to keep us informed and we will give any help we can.