I was going through the most consistent training of my life in March 2020 until I purchased some Nike Aeroswift Half Tights with a liner sewn in. I ran my usual 1 hour run and felt pain in my groin towards the end. I assumed it was due to a blister on the same foot.
I wore them for more runs and my groin got worse and worse. I couldn't start/stop suddenly or sneeze without pain. No speedwork at all. It took a long time to heal as my new long Nike tights also had this liner.
I stopped wearing them and only ran in my old shorts which do not have an elastic band sewn into the edges of the liner. For 2 months and my groin healed finally.
So I cut that elastic band out (the material has held up fine without it and it feels much better). I am in base training running same route same time same pace everyday. All the time no groin pain.
Yesterday I ran in my pair with the elastic band just to test and towards the end of the run my groin was sore same pain as before. I have cut the elastic out of that too.
Just wanted to share to anyone else having groin pain.