Hip adductor pain after running

It's hard to say without seeing you run (or doing a postural assessment...) but this does seem to indicate some sort of postural dysfunction. There are at least a couple of potential issues I can think of:

• Tight hip flexors (caused by prolonged sitting) are often associated with tightness in the adductors.
• Adductor magnus is a stabiliser of the hip, working against internal rotation. It could be a sign that your external hip rotators (primarily glute medius) are weak.

But as others have mentioned, it does sound like you're doing too much too quickly. Running is hard on the body, particularly if your alignment and posture aren't good. Take a break from the running before you consider anything else.

It sounds like you're running every day. You need to rest. Take a few days off until the pain goes away. If the pain lasts for more than a week without running, see a doctor. When you're good, start with your usual 3 miles, then take the next day off. Run about 3 times a week, always resting the day after. If you start feeling pain again, immediately stop. If all goes well, the next week you may increase your mileage. Most people recommend not increasing by more than 10% each week. In my opinion it's fine to increase your mileage faster for the first few weeks, as long as you're starting your runs fully recovered. It's also recommended to decrease your mileage from time to time, like once a month.

As for the specific cause of your pain, it's hard to tell, but it's possible that the stretching is making it worse. I'd recommend not stretching at all before or after running.

I actually think this is a fairly normal part of the adaptation process. Couch potato status is relative to running. With respect to running, you’re basically completely untrained.

The hip adductors are one of the most untrained muscles, especially in males. The fact that you’re using them while running and they’re getting sore indicates that your body isn’t used to that sort of stress.

I’d recommend only increasing total distance by about 10% each week. Give your body ample time to recover and don’t push through the pain too much. I suspect this will go away as your body gets used to running.

It's possible the groin pain may indicate hip issues. Do you happen to spend a lot of time sitting? Is the pain one sided? If so, it could indicate asymmetry in your hip musculature. You might consider one-legged exercises that target the hip like the pretzel.