Does my room / office need to be large to accommodate a massage chair or table?

Not at all. 

Massage chairs (ideal for companies, corporate events or home spa parties) utilise about the same space as an office chair.

Massage tables require a little more space as the standard size would be 1m x 2m, just clear 2x2 m of floor space for your therapist to set up the massage table, but often moving a coffee table provides ample room in a family room.

Any quiet space: family room, living room, or a patio can be easily adapted to accommodate a massage table.

You may also check How much weight can a massage table carry?