I suffer alot Nugent, I was also a chippy an its a hard job ( especially years ago ) we have all carried a 8X4 3/4" sheet of ply and not thought nothing of it, thats a awkward size and its not light

my knees are gone, I spent a total of just over 2 years ( over a 3 year span ) fitting 5 Lever deadlocks on council houses, 10 locks a day ( we got 1 hour each lock and had to do 2 extra to book 1 hours overtime ) , i knackered my knees

used to also play sports hard, football, Judo, mountian biking, running, they all have taken toll on my body

i have been to a few physios, they have sorted out my back, it mainly came down to posture in the end, stand up straight, head back, chest out, its helped me alot