Stomach sore to touch

Hi folks. I posted about this before but my stomach was very painful and tender to touch and very painful when I moved. This started about last October and is finally fully better, has been better for a few weeks now. I didn’t feel ill, had no other symptoms but my gp didn’t know what the problem was, he wasn’t particularly concerned since I wasn’t ill. I saw him a couple of times, by the second time I saw him it was still very painful but slightly better so gp thought we should wait and see if it continued improving which it did do and is totally fine now. I (and gp) had two theories about what the problem was. 1. I had just hurt myself which is possible but I can’t think what I could have done. 2. Since I inject betaferon (been on it for nearly 17 years now) and I nearly always inject it my stomach that I had somehow hit a nerve and caused the pain. This sounds to me like the most likely explanation cos the pain centered around where I typically inject, and also because of the way it gradually got better. So my question is has anyone ever caused a really severe amount of pain with an injection, I’ve had minor irritations in the past but nothing on this level. Just curious, that’s all. Thanks Cheryl:-)