Fed up with sore sites - thoughts please

I've now been on the pump just short of 4 years. I rotate religiously and each site ends up with a break of 3-4 weeks before reuse. I'm not using the centre part of my stomach around the belly button due to scar tissue from years of injecting. I use the very edge of my tummy all the way round to almost the back and then above the waist but below the ribs.

Like anyone I've had the odd sore site but lately I've had real issues with them almost all being sore. I've not lost weight or anything and I'm using Inset II 6mm as always. I recently has a run of occlusion alarms and was changing sets loads but (fingers crossed) that's sorted itself out. I've recently started bio oil on all my sites to try and heal skin plus taking Perfectil skin plus to help avoid long term skin problems. Yet every site feels normal when fired in but gets sore almost straight away. I'm so fed up. Weirdly my friend who has also been pumping 4-5 years on same pump and sets has complained her sets all seem sore but she thought it was scar tissue from pregnancy.

What do you think? What could be causing it and any suggestions on how to fix it?

Also just to add the sore sites don't seem to be effecting my BG rates. Just all very sore. Initially I was changing them because of soreness but now there seems little point and I just put up with the pain for 3 days. Sometimes it lessens and also I can take ibuprofen for it. Pumping isn't meant to be like this though

I must admit I hadn't considered the sticky causing it. It's certainly stuck very well when I come to remove them so don't think they are less secure. I also don't have any rash or skin reaction underneath and the soreness feels like it's inside, plus now it can be painful to bolus. I have just taken a cannula, cut the cannula part off and stuck it to me to see if I react.

My husband wonders if it's the bio oil or the skin supplement I'm taking doing it so I may have to stop those as well.