Discomfort after use

I think you are wise to stop using your device for a bit, at least until any discomfort passes. You shouldn't experience pain. When you feel you're ready to try again, begin with shorter sessions, perhaps 20 minutes or so, and try to minimize your kegels. It sounds like you may have some slight bruising or overuse of these unfamiliar muscle groups.

... the next day following each session I have experienced painful discomfort in the area below the navel and above the groin area which has lasted for several days.Is this normal?No, painful discomfort is not normal. What would cause this?I'm only speculating here but a couple of ideas come to mind. First, the type of lube you are using may be causing a mild allergic reaction, causing irritation, internal inflammation or gas production. The lube may also be disturbing the natural bacterial flora in your lower G.I. tract causing some system distress. You should consider trying a different type of lubrication for your next attempt. Second, you may have been performing overly strong kegel contractions causing your massager to slightly bruise your internal organs. Try easing back on the strength of the contractions you employ, it is not necessary to generate a great deal of movement or pressure for your Aneros massager to be effective. Third, you may have simply overworked your pelvic floor muscles with strong, sustained kegels and your muscles are naturally sore after a vigorous workout. Your muscles will tone up and be capable of greater endurance with continued practice, the fatigue factor should diminish over time and those muscles will no longer give you discomfort. Decreasing the time spent kegeling will help reduce the fatigue as well.
Good Vibes to You !

I think all you did was overwork your abdominal muscles trying to do kegels. There's almost no way the Aneros in your rectum can connect to some sort of pain in the abdominal region.

As I've suggested to others, put the Aneros in (which whatever your favorite rectal emptying procedure may be or lack thereof and your favorite lube) and relax for 10 minutes doing nothing, then GENTLY pull in with your urinary sphincter like you'd be trying to hold back pee--not pulling in with your anus--and while sustaining this gentle contraction, lightly tickle your nipples and see if you don't have some tickling feelings start in your anus accompanied by some warm feelings in your pelvis. Over time these warm feelings will grow into deep intense orgasms without ejaculation, the fun part of all this.

Sounds like live issue to me too, I've had similar issues. Shea or coconut oil is good as it's very easy on you.