Ah, so very many.
From desk jobs where we can place stress on the neck to lifting jobs which potentially affect the back and knees and jobs that involve repetition, such as hairdressing and working at a keyboard, many types of work can cause wear and tear.
Rheumatism is an overall term for problems of the joints and it is most likely that osteoarthritis (wear and tear), bursitis (inflammation of the fluids that lubricate the joints and repetitive strain injury (RSI) will result from years of similar activity.
For muscle imbalances and stiffness due to poor posture, combine magnesium with Arnica gel. For RSI and bursitis look at Devils Claw and Urticalcin, while wear and tear can be helped and even prevented by glucosamine or collagen with the application of some Arnica gel after a tough day.
Previous injury to a joint is also a common cause of rheumatism, so you may wish to look back through the years in order to explain a worsening ache, even if finding the cause doesn't do anything more than satisfy your curiosity.