Issues could be everywhere in your code or wiring...
To your general question:
I2C pull-up are resistor you put in parallel on your SCL and SDA lines to Vcc
They are documented all over the web including recommendations on how to choose the resistor value.. let me google an example for you.
I’m not sure this is the issue though. There has been a long heated discussion here (where I found @batata004 being totally off limits) but if you read the very last post from Jeff you’ll see in that summary that there are deficiencies that are hard to overcome and likely point at hardware and software issues in the Arduino Wire library.
If you don’t need DMP then things seems to work fine but if you need DMP then you are at risk of the wire library being locked in an infinite loop.
From personal experience it seems (just observation, I have not explored in deep details) that chances for this to happen increase when there are other interrupts going on and you can’t keep up with the fifo buffer. It means chances for this To happen increase when printing on serial at a fast pace, saturating output buffer and locking code in the print function. I’ve had some success by implementing mitigation techniques to throttle access to outputting data and discard erroneous buffers and not printing stuff out (using the info in a PID process)
How can I calculate the sample rate for MPU 6050 if the baud rate is 115200 and requesting 20 bytes of data as a string for LabVIEW?
At 115200 bauds you send roughly 11 520 bytes per second if there is nothing limiting the data being available for Tx. So 20 bytes would take 20/11520= 1.74ms so you could run say at 500Hz if there are no maths slowing down the code. I2C will also add its own limit (clock speed of 400 KHz) depending how much data you read off your sensor. (From theoretical 8kHz only for the gyrometer and 1kHz for the accelerometer).
But as said above I would expect issues at that frequency so implement a way to Throttle The Tx and optimize the packets’ size (use binary and not ascii or don’t slow down the arduino doing floats computation, just send raw data and do the maths on the other side if possible for example)