When you get hurt during training, should you self-diagnose your injuries, or should you go to visit a doctor? The first thing you need to determine is what resources are available to you, both in terms of what sort of insurance coverage you have and whether there are any competent sports doctors available.
Once you know what resources are available to you, the next most important thing that you need to consider is how severe you perceive your injury to be.
Be sure to note that what you perceive and how severe an injury actually is may have little correlation with one another.
Experience will be your friend here, and if you have any coaches, teammates, or friends that have more experience than yourself then you would be wise to ask their opinion.
Sometimes you can tell that something is very severe, such as when you break a bone and a piece is sticking through your skin.
Chances are pretty good that even if you are a physician yourself that you are going to need some competent help.
Other times, you can tell that something really is not very serious, such as when you stub your toe and it stops hurting after 10 or 15 minutes.
In those cases, you generally will know whether you need to go see a doctor or not.
The problem with sports injuries, especially non-contact sports such as running or weight lifting, is that you may not even notice the more severe problems while minor problems may seem like they really hurt.
For example, an oncoming stress fracture might seem like a minor shin splint, and tendonitis may begin by feeling like a sore joint.
If you do not adjust your training appropriately, then you may wind up having to sideline yourself for a season or even longer.
Then again, if you do not properly cool down after a marathon or other really difficult workout then you may find yourself unable to move the next day.
Realistically, even though you are in a lot of pain, there is not that much wrong with you and you will be fine within a day or 3.
The more that you exercise and the more that you compete competitively, the more that you will get to know your body.
Once you have had a sports injury or three, you will start to notice a trend when you begin over training.
If you keep accurate training logs and track your weight or your resting heart rate on a daily basis, then you will often be able to prevent the worst injuries in their early stages just by becoming familiar with your own body and its needs and taking extra rest whenever possible.
After considering your resources and trying to figure out how much pain you are in or are likely to be in if a change is not made, should you go to see a doctor or not? In general, I recommend going to the doctor if possible.
In my experience, most recreational athletes are not comfortable enough with their bodies and do not have a frame of reference to accurately judge how serious an injury is.
That being said, I very rarely go to the doctor.
Most of the times that I have, I have been disappointed with what they have to say or have already written an accurate diagnosis in my training log before I get there.
I have kept pretty accurate training logs for most of my adult life and am very comfortable with my body.
I also know exactly how much pain I am willing to put up with and I am not shy about backing off to prevent a minor problem from becoming a major injury.
If you have a similar familiarity with your body then it will be easier for you to avoid having to ask yourself whether you need to visit a doctor in the first place.