simple, train harder, change up your routine and rep ranges and train to failure, eat more and sleep even more! muscle growth is not an over night thing. it takes most pros 5 years to put on 10kgs of lean muscle. just remember this is a marathon and not a sprint race, being a sprint race will end up with injuries and damages that are not so easy to recover from especially when the muscles become way stronger than the tendons. try changing up your training style from usual straight sets to doing 100 rep sets, where you can pyramid up in weight whilst going down in number of reps, so do 20 reps and then rest 30 seconds, do another 20 reps, rest 30 seconds up the weight and bang out 15 reps, 30 seconds rest, up the weight, 10 reps, stay the same weight, rest 30 seconds and go again till failure, and u keep going up and up untill u get to 100 reps. then move on to your next exercise, start at a heavy weight and do 10 reps, stop,rest,another 10 reps,(these 10 reps should be to failure) then do a lighter weight and go for as many reps as u can(till failure) untill 100reps is reached. so in 2 exercises u have done 200 reps all with different rep ranges, some lighter weight till failure and some with heavier weight untill failure.
