I need a new secondary pitch

I’m 13. I’ve been throwing fastballs and curveballs for about a year. My travelball coach recently told me to not throw curveballs to preserve my arm. I have a good 65mph fastball but I know I cant strike people out with only that. Can someone suggest me a good secondary pitch?

I’m truly tired of people continuing the myth that a curveball is bad for the youth pitcher. If thrown correctly, the curveball puts no more, if not less, stress on the elbow/shoulder than a fastball. There are a lot of studies that prove this. For one such study go HERE
Little league was getting so many complaints from ill-informed spectators watching 12 yr olds throw curveballs on TV, they considered banning the pitch. They conducted a 5 yr study though University of North Carolina with over 1,000 pitchers from 8 yrs old to college. The result? 1. The relationship between age, type of pitch and injury risk is complex, but there was no clear evidence that throwing breaking pitches at an early age was an injury risk factor; and; 2. The data showed the primary cause of arm injuries is overuse, not the type of pitch. Details on that study HERE

So it seems like you already have a second pitch and need to educate your coach. Do this in a respectful manner by presenting your facts and asking for his.
For a third pitch, try working on a change-up. There are many grips for a change-up, so try many to find out which one works best for you. Some different grips are HERE

I know there are studies claiming the curve is as safe as a fastball but I have yet to read a study where I could tell they measured everything they should have. For example, the first study mentions measuring moment forces on the elbow. They then go on to mention supination and pronation:

As mentioned, the forearm did remain more supinated and the wrist more flexed during the cocking and acceleration phases of each curveball as compared to the fastball but the supination velocity did not differ significantly implying that this was also not the cause of the increased injury rates.

But while they talk about “supination velocity”, they don’t say anything about the degree of supination. Nor do they talk about rotational forces created by the supination. And words like “implying” appearing in studies(bolded above) always cause me indigestion.

Now, I’ll be the first to say I don’t fully understand all of the terminology used in these studies. But I prefer to qualify the claims of the curve being safe by adding that the number of curves thrown should be limited to no more than about 20-25% of one’s pitch total. And I also like to add that while the studies do mention using proper technique, it often requires the use of high speed video to verify proper technique is being used. It’s not clear if or how this was done in the studies.