What
MRT2 said.
At age 65 I'm facing the shoulder aches you described, and encroaching arthritis in my wrists. Some days by the time I got home I was praying for the ride to end.
The fix? I raised the handlebars and shortened the reach on my Cannondale hybrid PD for about $35. It got me more upright and kept me on an otherwise perfectly functional bike. I've had trouble "making peace" with the mental image of traditional swept back bars on that bike, but each time I price a new bike of parallel quality the $100 or less modification looks better and better.
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Current bikes: Unknown year Specialized (rigid F & R) Hardrock, '80's era Cannondale police bike; '03 Schwinn mongrel MTB; '03 Specialized Hard Rock (the wife's)
Gone away: '97 Diamondback Topanga SE, '97 Giant ATX 840 project bike; '01 Giant TCR1 SL; and a truckload of miscellaneous bikes used up by the kids and grand-kids
Status quo is the mental bastion of the intellectually lethargic...