Welcome to the forum, wildhorses.
It would help to know about you and your horse in terms of how old your horse is, how much training and what kind, how long you've had him, has this always been the problem or is it something new, how much experience have you had? What kind of feed and how much? How much turnout does he have?
How to correct the problem has a lot to do with what caused it, be it ill fitting tack, lack of training, lack of experience of the rider, or even the weather.
Let's start with tack since that should be the first place we need to correct. If your saddle is not placed right or is too large or small, that can easily translate to problems while riding. Some pictures would help. BTW, English or Western, and what kind of bit?
As far as training is concerned, I would suggest getting back to the basics of training and teaching your horse how to behave from the ground. A round pen is a great help at this stage. Without a pen it is more difficult but doable. I would long line your horse until you can move him up and down in all gaits. This may take a few times or a lot, it depends on how willing your horse is and how skillful you are.
Experience of the rider comes into play as well. If you do not know what to look for and how to counter it when your horse misbehaves then you need lessons before going further.
To counter a bold or agressive horse while on the trail, it helps to learn a "one rein stop". It also helps to get your horse thinking about you and not have time to quicken his gait. When he starts to quicken, start circling him - large circles if possible. Do serpentines, transitions, or anything but a straight line. He will eventually get the idea that it more difficult to work rather then go nice and easy.
Lastly, he should be ridden in a simple snaffle with minimal contact. If you need a death grip to rein him back then you need more ground work before the trails.
One last thing, actually, is the weather. A nice spring type day after the winter or a real blustery one can bring out the worse in a horse. They feel good and want to get rid of a lot of excess energy. Same thing if he is stalled a lot without exercise or on a lot of grain without being able to expell the energy.