Oil is full but pressure indicator comes on

I'm on mobile (my laptop as well as my bike needs repair!) and having trouble searching the forums effectively, so I apologize if this topic had been covered.

1996 Shadow 1100 ACE ... Just pulled out of winter storage. I didn't get around to doing any winter storage preparation like drain the fuel tank or anything. I pretty much just got the bike running, did some checks, and rode to work. about two thirds the way through the ride, the oil indicator lit. I posted on forums and did some tests, cross my fingers hoping that it was just a false alarm (didn't have another way to get home), and rode home. The ride was fine apart from the indicator coming on 2/3 thru the ride again. It's about 6-7 miles (11km).

I changed the oil and oil filter. The next ride to work had no oil indicator, so I thought the problem was solved. On the ride home the indicator came back on, earlier in the ride. Obviously there's an issue other than a clogged filter.

Anyone else had this? What did you do?

I'm calling the shop tomorrow to at least get a pressure test done, so I can know whether it's a real pressure issue or a bad sensor issue.

Thanks