Thank the eccentric contraction component ( lengthening of the muscle under load) of your exercises forceably damaging your actin/myosin cross bridges. Muscle cell contents leaked out, causing the cascade of events leading to inflammation and pain.
I agree with WarBoss Alex.
You lifted too much, after such a long lay-off. You should have just lifted 'the bar' the first few sessions. Patience is key after such a long lay-off. Anatomical Adaptation phase requires a few sessions at light weight/ low number of reps.
The neural recruitment patterns are first wave of adaptation, then actual muscle hypertrophy. Why force muscle hypertropy from the get go by using such a high load? Patience.
You should be fine, lift lighter and do less set or reps. 2x15 with little or no weight is standard during anatomical adaptation phase for the first 5-6 sessions, after than ramp up the weights and follow a periodization program.
A post workout recovery drink like endurox R4 may help as it has 4CHO:1protein, with antioxidants, and glutamine to promote recovery.
cheers, RD